Strange Problem (happened overnight!)

[mightyboosh]

Hello!

i'm here again to shoot off amature doubts.

Right, so i normally keep my computer on over the night to get things downloaded (using torrents, to reduce the threat of a virus)
So then, i wake up in the morning today, and shut down the computer like i normally do..go do my daily things.

Now when i get back and i start my computer, it took 10 minutes on the scrolling worm screen, and i had to reboot..after many attempts, i've managed to get it on, i have 512 MB ram, but it looks like it's running on a 128 right now.
(I checked my processes under task manager, and it doesn't show me anything abnormal)
Although, when i was checking with AVG free, it told me that a system file had been 'changed' (some file in the system 32 folder)
Now i know that that's not a good thing, i just don't know what to make of it..

1. Is it a spyware (because i don't have active spyware protection, please suggest a good spyware, apart from AVG)

2. Should i format my C: and everything will be okay?

3. Can it be a hardware problem, because i'd faced a hardware problem like this and AVG told me that system files had been 'changes'

Please tell me what i should do!
Thanks..
__________
The file that reported a change is called 'ntoskrnl.exe' in the System 32 folder

[s_aerin]

ntoskrnl.exe is a bootscreen file if i am right, and yes its probably a virus. use avg or adaware for scanning.

[mightyboosh]

Did that.. AVG doesn't detect any 'threats' (as i said earlier, it just says that file's been changed) and i don't have an active spyware protection..

Any other suggestions?

[Pathik]

1. Use avg+zonealarm+spybot snd.. 2. Yep 3. No

[mightyboosh]

Thanks Pratik

[sumeetindia]

It may be a virus use AVG updated to check

If eveything fails

use the second option

[aneesh kalra]

Ntoskranl.exe refers to the kernel of your os.Are you using vista by any chance.If yes than this is interesting considering that vista actually said that it does not allow access to kernel.The virus has modified your kernel check msconfig for any suspicious enteries.locate the registry key the virus may hace created and delete it.better use kapersky.