I looked up a new model year chart.  With the 3450's being introduced in 2021, if in warranty, you may need to contact Warranty Support.

Well, if it were a virus or malware, then I don't think it would still work on some days.

Upon startup (before Dell logo and before keyboard light) press F12 a few times for the menu that has boot and diagnostic options.  Two diagnostic options are "quick" and "full."  If "quick" doesn't find anything, you'll end up running "full" anyway.  "Full" can take a few hours; can always let it run overnight.

If nothing comes up, try a different HDD/SSD.  It would be considered unusual for 2 separate systems to both develop HDD/SSD problems at nearly the same time, but may have to rule it out if diagnostics doesn't show anything.

How new are your 3450's?  A chart I have doesn't have them listed, and it doesn't list all models anyway.

i posted here, to see if anyone has some insight.  i then did post a service tag request, waiting for reply.  if it IS something serious, that i swhy i'm posting now, so i can get it fixed under warranty.  BUT, since TWO of same machines do it, it sounds like something that may not be machine-specific, and i'm hoping someone can add some insight on this

i replied to your second post before i saw the frirst.  thanks for the sugegestions. i will try them this week.

thanks

There are some scenarios that could be pursued :

-if both of them got a recent bios update, the new bios could be messing up

-they could be part of the same build batch ( same mb batch by example, or same production batch for the psu ) and that batch has some components that have some small defect

-it could be a driver or application running on both, acting up

In case you want to troubleshoot it yourself, there is a standard scenario not requiring system debugging skills:

1)Try booting without freezing. Usually you need to initiate a safe mode boot (google how)

2)In the "safe mode" check the "event viewer" tool for errors in "system" log inside the "windows logs" folder.

The error preceding the freeze may point out the cause. There will be an error code (like IRQ not equall or less etc), or a name of the driver, or the event itself may hold a name of the system service that fails (like nvidia....somethig)

Some kernel fault codes are listed here: https://www.lifewire.com/blue-screen-error-codes-4065576

If there is no comprehensible information in the log, your last resort is memory dump.

There are 2 dumps actually, mini and full BSOD dump.

So you need two things:

1)Microsoft debugger from Visual Studio. You need to install only debugger, leaving other programming stuff aside.

https://docs.microsoft.com/en-us/windows-hardware/drivers/debugger/debugger-download-tools

And if there is no internet connection, you need the debug symbols pack https://docs.microsoft.com/en-us/windows-hardware/drivers/debugger/debugger-download-symbols

then you need the KDFE script.https://asuhovey.wordpress.com/2007/01/28/kdfe-cmd-a-simple-kernel-debugger-front-end/

Kdfe script is somewhat old, so you have to edit it, changing the path to the latest debugger exe installed in your system. Put the kdfe.cmd somewhere where Windows may find it by common path, like in C:\Windows, or C:\Windows\system32.

After that, open the Admin console (type "cmd" in "Start-search", hold CTRL+SHIFT, and press enter, windows will ask for elevated privileges for the console). Simply type "kdfe", and choose which system dump you want to analyze. The debugger will scan the dump for a few seconds, and give out the driver, or any system component which had probably caused the BSOD.

ok, this is a long post

this is my SISTER's machine (mirror of mine).  it froze this morning.  we then ran the diagnostics, BRIEF and EXTENDED, and it was successful, no errors.  we then got it rebooted,and we decrypted bitlocker, to take one more thing out of the picture.  we then rebooted, and it rebooted.

NOW, HERE is the SYSTEM EVENT log, couple criticals , several warnings.  some of the warnings still persist, since after the successful restart.

here they are, and any feedback on them is appreciated

The machine-default permission settings do not grant Local Activation permission for the COM Server application with CLSID

{C2F03A33-21F5-47FA-B4BB-156362A2F239}

 and APPID

{316CDED5-E4AE-4B15-9113-7055D84DCC97}

 to the user HOME21\user01 SID (S-1-5-21-391981318-3510243720-4046636942-1002) from address LocalHost (Using LRPC) running in the application container Microsoft.Windows.ShellExperienceHost_10.0.19041.1320_neutral_neutral_cw5n1h2txyewy SID (S-1-15-2-155514346-2573954481-755741238-1654018636-1233331829-3075935687-2861478708). This security permission can be modified using the Component Services ad

12/28/2021, 8:54:29 AM, event id 10016

The application-specific permission settings do not grant Local Launch permission for the COM Server application with CLSID

Windows.SecurityCenter.WscDataProtection

 and APPID

Unavailable

 to the user NT AUTHORITY\SYSTEM SID (S-1-5-18) from address LocalHost (Using LRPC) running in the application container Unavailable SID (Unavailable). This security permission can be modified using the Component Services administrative tool.

12/28/2021 8:51:36 AM

The application-specific permission settings do not grant Local Launch permission for the COM Server application with CLSID

Windows.SecurityCenter.WscBrokerManager

 and APPID

Unavailable

 to the user NT AUTHORITY\SYSTEM SID (S-1-5-18) from address LocalHost (Using LRPC) running in the application container Unavailable SID (Unavailable). This security permission can be modified using the Component Services administrative tool.

The application-specific permission settings do not grant Local Launch permission for the COM Server application with CLSID

Windows.SecurityCenter.SecurityAppBroker

 and APPID

Unavailable

 to the user NT AUTHORITY\SYSTEM SID (S-1-5-18) from address LocalHost (Using LRPC) running in the application container Unavailable SID (Unavailable). This security permission can be modified using the Component Services administrative tool.

The browser service was unable to retrieve a list of servers from the browser master \\HOME on the network \Device\NetBT_Tcpip_{DEFA41D3-B423-4011-BFF3-2969DC9CA865}.

 Browser master: \\HOME

 Network: \Device\NetBT_Tcpip_{DEFA41D3-B423-4011-BFF3-2969DC9CA865}

 This event may be caused by a temporary loss of network connectivity. If this message appears again, verify that the server is still connected to the network. The return code is in the Data text box

12/28/2021 8:50:47 AM

EVENT 8021

The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.

EVENT 41 – critical - 12/28/2021 8:49:31 AM – task category 63

The driver \Driver\WudfRd failed to load for the device ROOT\PARAGONBLOCKDEVICE\0000.

12/28/2021 8:49:29 AM    event 219, task 212

The previous system shutdown at 8:19:47 AM on ‎12/‎28/‎2021 was unexpected.

12/28/2021 8:49:35 AM , event 6008

The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.

12/28/2021 8:16:19 AM    event 41, task 63

Hi there, I'm a bit late to reply but I have this exact same problem with 2 3450's.  I tried updating everything, but it almost seems like hardware at this point.  I had 2 new ones shipped out, and I would swear that one of them is still freezing.  Have you found any solution to your problem?

how did you get two new replacements?  when did you purchase your original machines?

background on ours -  we bought two machines in july/august 2021.  we had some intermittent freezing about one month later, it was rare, so we tolerated it (my sister and i bought identical units).  but, then it started to get worse;  first her mahcine, then mine.  we filed a service request in december.  since that point, i can document at least ONE HUNDRED HOURS in trying to fix this.  I've got 40 years of computer experience, and i know that intermittent issues can be hard to diagnose.  BUT, i believe dell should have replaced these units for us by late december.  we did request that;  they declined, said it had been too long.  my sister tried to file a mastercard chargebck, but they said it was too long.  the NICK machine (mine) went back for depot service (they shipped us a box to send it back).  they shipped it back to me, said they "reloaded the operating system".  during that time, they LOST all the dell software AND the Cybelink software that came with the DVD.  My sister's machine was sent for depot service, they said they are replacing the motherboard, we are awaiting that one (the SANDY machine).

I am reloading all my software, configurations, customizations, etc;  i waited until the windows 11 update occurred.  so far, for the NICK machine, since depot sending, i have not had it freeze, but i am very wary.  at the first sign of any freeze, i am going to file a better business bureau incident.  I am STILL going to do that for the CYBERLINK software, but want to first get the NICK mahcine fullly runing, and see what it does, and also get the SANDY machine running and see the results.

AGAIN, i have all the logs of service documented/recorded, and i have over one hundred pages in microsoft word with this.  we uninstalled/reinstalled factory images, windows images, etc.  we did numerous hardware tests, etc.  NEITHER of our macihines showed any hardware issues with teh diagnostic stuff.

I am convinced that this may be beyond even a dell issue.  if you search for "machines freezing", there are others with the issues, but people seem to be tolerating them , and they seem to be less than the frequency i've had.  BUT, they are occurring.

I do not know if there is just a glitch as all these programs try to run, interact, etc.  All I know is this is the worst experience i've ever had in over 40 years of dealing with comptuers.  we BOUGHT dell because we have four other dell machines, and the prior ones have been reliable.  This has been a big disappointment.

The SAD part is that the 3450, with 16 gig memory, 512 g SSD drive, intel fast processor, when it is running correctly, is a GOOD machine.  I believe dell dropped the ball in working with our machines, because they could see from even my initial attempts at diagnosing these machines, that i had taken care to document what was done, test teh memory, check for updates, etc.

the software that we have installed is mainstream software, we do not do a lot of gaming, etc;  we just run the mahicnes to handle our photo's, finances, etc.  all the software that i have installed is running flawlessly on the OLDER dell machines.

please keep replying as to how your interaction with dell goes, and also pleaes reply as to the question above, the timetable from when you bought machines.

thanks

I started troubleshooting in early January.  After trying everything that I could, short of reloading the OS, I finally contacted Dell.  There were no logs, no events that pointed to any particular issue.  I thought peripherals might be causing the issue, but that wasn't the case.  In the end, contacting Dell and walking through with them the same steps that I had already done I essentially stated that it seemed like hardware.  Luckily, they were able to get me the 2 new pcs within 3 weeks, and as of now, it seemed like it was going to be locking up again so I installed a fresh copy of Windows instead of Dells image.  I'm cautiously optimistic, but I think I've seen the machines freeze preboot.  I will keep you updated.