delayed write failed alert

[poastell]

My PC looks to have a virus hiding behind a 'delayed write failed' alert.
First enquiries suggested it was a failing HDD and a 500Gb usb drive disappeared but later this mounted OK and all drives have been accessible.

other symptoms:
BIOS set up inaccessible via delete key
safe mode inaccessible, the options screen appears but the keyboard is locked
after a restart the machine was frozen but later, ie now, it runs firefox and thunderbird OK
Avast was able to check some of the drives but others appeared inaccessible.

Avast free is a very elegant app. but how come it didn't catch this virus? I haven't been able to find recent reports here of this problem, does anyone have a fix for it? Where does the virus live? Can it be removed?

NB this PC is running xp pro on an asus motherboard with two onboard IDE drives and three usb drives.

[Pondus]

Avast free is a very elegant app. but how come it didn't catch this virus?

No security program have 100% detection......if they did the virus problem would be solved


if you think you are infected, follow this guide and attach (not copy and paste) requested logs
http://forum.avast.com/index.php?topic=53253.0

[poastell]

Ok thanks I'll get on to it. may not be very soon though.

[poastell]

Following your suggestion I ran mbam
First on the PC without the three usb drives (and with network and Avast turned off)
result as attached.

I then mounted the most critical 500Gb J: usb drive with 5 partitions/drives
and ran mbam again. (but forgot to disable AVAST).
the scan froze after 1m 51secs on a file in Thunderbird MAIL backup folder.
with the usual 'delayed write failed' alert
windows was frozen.
there was no access to task manager

I shut down drive J:
this freed off windows
task manager appeared
and I was able to close the My Computer window

At this point ( shutting down the J: usb drive) the mbam window jumped from the info accompanying the freeze (8 lines above) to saying '209482 objects scanned no malicious items were detected' after 53 minutes.
The mbam tabs were inaccessible and no log was saved.

Also later : updating spybot disabled this app. there was a message: 'SDhelper.dll marked read only'.

F8 key still gives a frozen options screen and the BIOS is also still inaccessible, however without the usb drives the PC runs Thunderbird and Firefox apparently as usual.

I'd welcome suggestions for further work to clear this problem.