Last night, set Microsoft Updates to run and to shut off PC when done. In morning cannot boot up. Error message is UNMOUNTABLE_BOOT_VOLUME. Tried safe mode, nothing. Tried to boot up with XP Reinstallation CD, but won't boot. No CD drive start. Tried CD in other PC and boots to Setup ok. Any ideas? Bob

Found this by googling. http://support.microsoft.com/kb/297185 Check in the bios, that cd is set to first boot device. Also, while there check if cd is actually seen in the bios. Before posting try google. Backup. Use anti virus software.

Thanks for the Microsoft support page. How do I check the bios as asked? Bob

I think DELL uses F2 for the keystroke to enter the BIOS. They call it the setup. Watch the screens when you first start the computer and there should be a message as to what key you tap to enter the setup. At any rate tap continously until either you enter the BIOS or you get to the same error. Getting to the error means you started tappin to late or you are using the wrong keystroke/s.

Thanks OtheHill, but there is no keyboard response. Saw the Setup as F2 and tapped, but could not enter Setup. Tried it 3 times, early and often.. Tried all the F keys. It just takes me to the mode screen and no matter what I select I get to the Unmountable error. Still cannot start reinstallation CD. Stuck here.. Bob

Are you using the Dell Kboard that came with the computer? Did you watch the screens for help? You may need to go to the Dell site for help on which key. Try del, you need to start tapping as soon as you tunr on the computer.

Good thinking O - was using my older Compaq keyboard - switched to the Dell and got into Setup. The CD Rom is listed as 4th of 5. Should I try to change the boot sequence and move the CD drive to first (so I can run the reinstallation CD)? Bob