Need BIOS settings - Optiplex 990 USFF Win7 64 bit w/SSD won't boot into Windows after CMOS battery replacement

Back-up disks and copies from other machines won't change settings in BIOS, so that's not going to help.

Do you see the Dell "splash screen"?

Do the 4 diagnostic LEDs on the front panel blink and then go off? Or do you get an error code?

What color is power button and steady or blinking?

Do you see any error messages?  

Did you reset the date/time in BIOS?

Boot Options are Legacy or UEFI, according to the manual. Is this set correctly?

Is SSD still first in boot sequence in BIOS?

Does BIOS correctly report the SSD on SATA0 in BIOS?

Is USB boot enabled or disabled in BIOS?

Is chassis intrusion enabled or disabled in BIOS?

Thanks for your reply, I really appreciate it.  Answers to questions below

Back-up disks and copies from other machines won't change settings in BIOS, so that's not going to help. Do you see the Dell "splash screen"?

Yes

Do the 4 diagnostic LEDs on the front panel blink and then go off? Or do you get an error code?

No error code.  Splash screen appears, it tries to boot into Windows (in either of the Safe modes, or normally), the Windows boot fails, and the computer reboots.

What color is power button and steady or blinking?

Power button is steady.

Do you see any error messages?

The only error message is when trying to switch to UEFI in Boot options, see below. 

Did you reset the date/time in BIOS?

Yes

Boot Options are Legacy or UEFI, according to the manual. Is this set correctly?

Boot options are set to Legacy; if I try to switch to UEFI, I get a "No file system" error (not sure of the exact wording, but this machine appears to be pre-UEFI)

Is SSD still first in boot sequence in BIOS?

Yes

Does BIOS correctly report the SSD on SATA0 in BIOS?

Yes.  I've run Thorough Diagnostics, all hardware tests correctly and displays properly in BIOS setup.

Is USB boot enabled or disabled in BIOS?

I've tried both enabled and disabled with the same result.

Is chassis intrusion enabled or disabled in BIOS?

I haven't seen that in BIOS, but will check.

Chassis intrusion is disabled.

Don't know if it's useful, but when I boot into Safe Mode, it scrolls through the registry and exits when it reaches three items with avg prefixes: Windows\system32\drivers\avgbuniva.sys, avgbloga.sys and avgbidsha.sys.  The PC had AVG anti-virus installed.

Thanks,

Myles

Power button steady, but what color? Have you tried booting with all devices disconnected, except mouse, monitor and keyboard?

Do you have any bootable CD or DVD, or any bootable USB? Put the disk in the drive,  or plug in the USB, reboot and press F12. Look for option to boot from optical disk or USB, whichever you're using.  Does it boot that way to a C: prompt or load some installation software? (Just cancel it, if it tries to run something.)

Windows was probably installed using the Legacy setting, so you will get that error if you change BIOS to UEFI because it can't find a UEFI boot manager on the drive.

Reboot and immediately press F8. Go to advance boot options and look for "Last Known Good". If that gets it to boot, shut down normally and reboot. If that works, shut down normally and reboot one more time.

And if it still works, you should be good to go, but back up personal files on external media ASAP, to be safe. Are they already backed up elsewhere?

If Last Good doesn't work, reboot and press F8. Look for the options to repair Windows.

If there is a Dell ISO for your PC, you would need the PC's service tag # to find out.

www.dell.com/.../win

Have you tried setting the SATA setting back to RAID? And seeing if the PC boots up?

Hi Ron -

Thanks for your reply.  I don't have any boot media, which is why I mentioned trying to get something set up earlier.  I neglected to create any boot media when the machine was up, which is pretty embarrassing.  Unfortunately, my only other Windows machine is also down, so I can't create anything - I would need to jump through the hoops to download a Dell OEM iso file, I guess.  I bought both of these machines used, so I have no Windows CD (these machines are for my wife, who's a translator; I run a music studio on Macs).

Anyway, the power light stays on and is blue.  

I've tried the "last known good" option before, with the same results.

As I have another machine down with terminal slowness (a virus, I'm assuming), I think I'll just turn them over to a local repair shop and let them take care of whatever's wrong - I've spent way too much time on them already.

Thanks,

Myles

Yep, I've been through pretty much every option in the BIOS menu that I can find.  It'll hit the beginning of the Windows splash and then reboot.  As I mentioned above, if I boot into safe mode the rolling registry list always stops at three AVG .sys files... I'm wondering if they're the culprit.

Thanks,

Myles

I don't think Dell has ever offered downloadable ISO files for Win 7.  

Did you try a Startup Repair from the F8 menu?

You could strip it down to bare essentials. Remove motherboard battery and press/hold power button for ~30 sec.  Remove all PCI-e cards, except video, disconnect all drives except boot drive, remove all RAM modules except the one in slot 1. Reinstall the battery (right-side-up!) and see if it boots now with only mouse, monitor and keyboard connected.

If you're willing to upgrade to Win 10 before the end of this month, you can still do it for free using the Win 10 ISO file that you can download from Microsoft. (The free upgrade offer ends 12/31/17.)

www.microsoft.com/.../windows10

That site shows you how to create a bootable USB and run the Win 10 installation.  There's always a risk you will lose your files, so I hope they're backed up on external media. Maybe a friend will let you create the Win 10 USB on their PC..?

Alternatively, maybe you could borrow or buy (check eBay) a Win 7 DVD from somebody. As long as you have the Microsoft Product key sticker on the PC that's still readable, you don't need to buy a new Product Key from Microsoft. And disks being sold without a Product Key should cost less too.  An OEM Dell Win 7 Reinstallation disk won't even ask for a product key as long as you're repairing or installing the same version of Win 7 that came with the PC, eg Home or Pro.

Dell does offer Windows 7 ISOs at least for certain PCs with certain service tag numbers.

I downloaded one about a month ago for a Latitude E6230 that I bought used.