kmcstech
1 Copper

Optiplex 755 USFF will not boot after changing cmos battery

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I have an Optiplex 755 USFF desktop computer that required the cmos battery to be replaced. After replacement the computer will not boot. It brings up the start windows menu, sasfe mode, safe mode with networking, safe mode command prompt, last know good configuration and start normally. Any option will bring up the WIndows XP load screen and then the computer re-boots right back to the start screen. One big loop. I can get the hard drive to boot in an Optiplex GX280 without issue. I was told the motherboard needs to be replaced but I switched system units and the same thing happens with this hard drive.

I've tried to reinstall the OS and get all the way to "starting windows" and then the blue screen of death stop error 0x0000007B (0xF7A10524, 0xC0000034, 0x00000000, 0x00000000). The computer is WIndows XP SP3, 1GB ram with 80 GB hard drive. It appears that setup doesn't reconize the hard drive.

Any help would be appreciated. 

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kmcstech
1 Copper

Re: Optiplex 755 USFF will not boot after changing cmos battery

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After several hours of experimenting, I finally figured out the correct BIOS settings in order to get the computer to boot. There are three BIOS settings that have to be changed or checked from default settings to get it to work. SATA 0 must be on, SATA operations must be changed from AHCI to ATA, and under modular bay the default "on" setting must be changed to IDE. Save the settings and the computer boots right up.  

TLeeDeYoung
1 Copper

RE: Optiplex 755 USFF will not boot after changing cmos battery

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Rescued my Optiplex, too. Thanks!

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18 Replies
7- Gold

Re: Optiplex 755 USFF will not boot after changing cmos battery

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Hi kmcstech,

Perhaps you are new to computers, but when you replace the CMOS battery, you need to boot directly into the BIOS and restore the settings you had before you swapped the battery.

There are two settings you likely need to fix based on that blue screen error. First, find the section of the BIOS called SATA operation. The default is AHCI. You probably need to change this to ATA.

Second, find the drives list, and make sure both SATA 0 and 1 are ON.

Then see if the system will boot.

kmcstech
1 Copper

Re: Optiplex 755 USFF will not boot after changing cmos battery

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My error was not writing down the settings in BIOS before replacing the battery. I felt resetting to default settings was a safe bet.

After replacing the battery, it immediately stopped with a message that date & time needed to be set along with system management. Press F1 to continue or F2 go run setup. I pressed F2, entered the date and time, saved the settings and exited. Upon re-boot is when the loop - reboot occurs.

I changed the SATA operation from AHCI to ATA. Second I checked that SATA 0 was set to on. There isn't a SATA 1. I saved the setting and re-booted. I have the same problem, nothing changed. Booting regularly from the hard drive gives the "start windows" options of safe mode, safe mode with networking, safe mode command prompt, last know good configuration and start normally. All of the options will display the WIndows XP start screen with the blue dots going across the bottom and once they go across the computer will re-boot.

I've tried the re-boot with 3 different hard drives, different makes but all 80 GB at 7200 rpm. None of them work in the 755 Optiplex but they all work in an Optiplex GX280.

Any other suggestions as to what I can try?

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7- Gold

Re: Optiplex 755 USFF will not boot after changing cmos battery

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I wouldn't just swap drives into the system willy nilly. You need to try to boot with the drive loaded with the OS for this system.

At this point, you're going to need to perform a repair install. For that, you'll need to boot to your Dell XP disc.

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kmcstech
1 Copper

Re: Optiplex 755 USFF will not boot after changing cmos battery

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All of the hard drives I've swapped are of the same size and speed as the original drive. All of them have Windows XP service pack 3 on them. In trying to determine if the original hard drive failed I swapped it into another Dell computer and it boots just fine. There I concluded that the problem is not the hard drive.  Clearly there is a setting in BIOS not set correctly.

In my original post for help I explained that I can't do a repair install or any install for that matter. Here's what I posted and happens when trying to install:

I've tried to reinstall the OS and get all the way to "starting windows" and then the blue screen of death stop error 0x0000007B (0xF7A10524, 0xC0000034, 0x00000000, 0x00000000).

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7- Gold

Re: Optiplex 755 USFF will not boot after changing cmos battery

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As long as the controller mode is set to ATA, that 0x7B error should not be happening. Unless, that is, there's a problem with the drive itself or the boot sector. Given that you've tried three drives, I think one of them has got to be good. So that leaves the boot sector. Are you deleting ALL existing partitions when you start the installation process?

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kmcstech
1 Copper

Re: Optiplex 755 USFF will not boot after changing cmos battery

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After several hours of experimenting, I finally figured out the correct BIOS settings in order to get the computer to boot. There are three BIOS settings that have to be changed or checked from default settings to get it to work. SATA 0 must be on, SATA operations must be changed from AHCI to ATA, and under modular bay the default "on" setting must be changed to IDE. Save the settings and the computer boots right up.  

7- Gold

Re: Optiplex 755 USFF will not boot after changing cmos battery

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Excellent! Glad that worked. Thanks for posting back.

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dogjawinc
1 Copper

RE: Optiplex 755 USFF will not boot after changing cmos battery

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Just for edification, I had a an Optiplex 760 with the same problem after changing the CMOS battery (same error, BSOD, etc.)  I was panicked because I had just re-installed the OS after an HDD change and done ALL the updates.  The scary part is that Windows kept wanting to go into recovery mode.  Who'd a thunk it was the BIOS?!  I'm not even sure the 755 and 760 have the same or similar mobo's, but AHCI to ATA did the trick. Thank you, Osprey!

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rusmag
1 Copper

RE: Optiplex 755 USFF will not boot after changing cmos battery

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Thanks for your post on correct BIOS settings..