Mystery Virus

[Scully]

My laptop has been rendered virtually unusuable by a mysterious virus. It
started only yesterday & I suspect it was one of those worms that starts on
a certain date because I hadn't used it to connect to the Internet for
several weeks, I can't understand how the virus could have got in there
yesterday since it doesn't even have a floppy drive.

McAfee reported some virus affecting SVCHOST.exe & it said it cleaned it,
after that I've run McAffee again with updated definitions (dated today) as
well as other utilities provided by them, like the bugbear detector &
'stinger'. Nothing has been found, yet every time I restart Windows the
memory usage builds up till it reaches over 1Gb all by itself, even without
opening any applications. As a result anything you do takes ages & programs
end up crashing or just do not lauch. Windows warns about low virtual
memory.

The task manager shows 'explorer.exe' taking up to 250Mb of memory without
doing anything, still it doesn't show anything that could explain the usage
of over 1Gb of memory. The HD light is constantly flashing all by itself.

Is there anything I can do short of reformatting & reinstalling Windows?

Many thanks

 

[PT Wang]

McAfee reported some virus affecting SVCHOST.exe & it said it cleaned it,
after that I've run McAffee again with updated definitions (dated today)

as

Windows version?
Does this happen in Safe Mode?
Does it always happen?
Which user ran SVCHOST.exe? Was that a user account or a system/service
account?
If the definitions were updated online, was the computer behind a firewall
during the update?

The task manager shows 'explorer.exe' taking up to 250Mb of memory without
doing anything, still it doesn't show anything that could explain the usage
of over 1Gb of memory. The HD light is constantly flashing all by itself.

Was that the only explorer.exe? Are you sure the spelling and spacing were
correct? Which user ran explorer.exe ?