Hi, I have been fixing my Uncles new PC, Cleared many viruses, eg: sp.exe and explore.exe.

But for sum reason it started going 'weird'

Whenever we logged on the monitor would say it was going into power save and the power light on the PC would dissappear. Then the hard drive was makign some very weird sounds.

Could it possibly be the HDD over heating or a virus, or even windows being well and truly knackered.

Cheers,
Luke

Noisy hard drives are not good. Do you know the manufacturer?

You will find the major brand diagnostics listed here:

http://www.tacktech.com/display.cfm?ttid=287

With a few others listed here:

http://www.ultimatebootcd.com/

I doubt that this would affect your monitor tho.

Try booting into Safe Mode by repeatedly tapping the F8 key after your BIOS POST but before Windows starts.

Check your settings via Control Panel > Display > Screen Saver > Monitor Power

Hi, when i booted in safe mode windows was loading all the files, got to the end and then the same thing happened, does that mean the harddrive is kaputt?

if the harddrive was broken and didnt work, you would probably get "primary drive 0 not found"
is there a "standby" or "monitor power off time" option in the bios?

you could try a repair install... a good guide here: http://www.michaelstevenstech.com/XPrepairinstall.htm