It would be simple...but would not work. The driver for starters on both systems are much different. The Windows OS on the Inspiron is digitally Licensed to the Inspiron and will not activate on the 420. And since the OS originally on the almost 12 year old system was Vista, there is no upgrade path for Windows 10. That is a pretty old desktop and time to retire it and look for a new, modern, up to date system that will run today's software reliably.

While Cloning works its not recommended because drive settings are not the same for SSD.  Too much writing to an ssd and you write it to death.  This includes the automatic defrag that is set on hard drives.  Moving drives between different hardware would have STOP 7B inaccessible boot device error.

I plan on swapping out the existing harddrive with an ssd drive then loading a fresh windows 7 or Windows 10 if it will work.  I see people were upgrading to windows 10 successfully on their XPS 420s but I was wondering if I could go right to installing windows 10 on the new installed drive rather than loading windows 7 and upgrading.

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@702displays wrote:

I plan on swapping out the existing harddrive with an ssd drive then loading a fresh windows 7 or Windows 10 if it will work.  I see people were upgrading to windows 10 successfully on their XPS 420s but I was wondering if I could go right to installing windows 10 on the new installed drive rather than loading windows 7 and upgrading.

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XPS-420 should handle Windows-10 (and a SATA SSD). However, not really worth the trouble unless XPS-420 is true quad-core and has at least 4gb or memory.

Disconnect the spinning HDD. That will be your backup.

Install only SSD and try clean-install.

https://www.dell.com/community/Alienware-Desktops/M-2-NVMe-bootable-options/m-p/6073037#M3399

I think only Windows-7 PRO qualifies for free upgrade to Windows-10 these days.

Thanks for your input.  I need to see this project through and finish this machine.  I pulled the old hard drive, put the new ssd drive in.  All I did was connected the same power and sata cables to my ssd drive that were on my old drive. Is that correct?  I put a fresh copy of windows 10 in the dvd drive and it says no boot device available??? I looked in the boot order and my dvd drive isn't there.  I'm assuming my drive is bad or not connected correctly, right?  I tried booting from usb also and it says there's no usb available in the boot order.  Any suggestions? Other than trashing it and getting a new pc :-)

Items do not show up in BOOT order until they are partitioned and formatted and installed.

You will have to manually F12 and choose dvd or usb flash drive.  That has to be an actual bootable media for it to work.

My dvd and usb drives all worked before I swapped out the hard drives.  I would think that they would show up in the boot devices.  Normally, this is an easy task.  Something simple is wrong and I can't see it.  I'm just getting a No boot device available error.  Maybe my windows 10 disk is defective??? Should I put the old drive back in and do a bios update???  Thanks for your input.

If you inserted the USB or CD, restarted the PC, entered the BIOS, and moved the USB or CD to the #1 spot in the boot order and saved and exit the BIOS it should work (Owner's Manual page 180 under Boot Sequence). I am suggesting the method on page 187 of the Owner's Manual, titled "Changing Boot Sequence for the Current Boot".

I actually skipped the F12 part and expected it to just boot from the dvd drive since I have USB or CD drive selected as the #1 spot in the boot order. So you're saying the dvd drive with the boot disk should show up even though it's not showing any details of that drive now?  

Thanks, I'm going to print these sections out and give it another try. I'll keep ya posted!