proponent

Thanks, everybody. I booted from the XP CD (I hadn't known you could do that) and then renamed ctoss2k.sys (it's size, by the way, was 126760 bytes, not one of the standard sizes). I'm now able to use XP normally.

Thank you, but my attempts to boot in safe mode have led to the same result as before: nothing happens.

On Aug. 27, I attempted to download and install updates from the Microsoft website. During installing, a BSOD appeared. It mentioned the file ctoss2k.sys . Unfortunately, I neglected to jot down the error-message numbers. There were three updates to be installed, one of them being a new Audigy driver. Since then, my Dell 8300 will not boot to XP. After I turn the machine on and select XP (I dual boot with XP and a non-Windows OS), I get a blank screen and nothing happens. I've followed the help wizard on the Dell website. No change. I've tried booting to safe mode, booting to safe mode with command line, and turning off automatic re-boot. No change. The system passes the hard-drive diagnostic and the other OS works just fine. Therefore, I suspect the problem is in software rather than hardware. At this point, all I can think of doing is re-installing XP (which will mean re-installing the other OS as well), but I'd *really* rather not have to go through all of that. Would anybody have any better ideas? Thanks much.....