Windows 7: Fresh install of Win 7 - Running slow as hell + keeps freezing

I installed Windows 7 Pro on my dads Toshibia C660 10T laptop after he caught numerous viruses.

I formatted and deleted the original partion, then re-installed windows. I have done this loads of times on many computers.

I downloaded the drivers for the WLAN and then connected to windows update.

My 1st update went well, 99 updates. Then i had some more updates which several faild for no apparent reason.

From day one of installing Windows 7 on his laptop, its been running stupidly slow and freezes regularly. Task manager says that 0% CPU is being used and 24% Memory is in use. It only has Vipre antivirus installed on it, nothing else.

Do you have any suggestions? I don't want to re-format it.

Oh, earlier i booted it up and it came up "Can't find boot disk, press CTRL + ALT + DEL to restart". I did this several times and it wouldn't boot to windows. I used the windows 7 disk to "Re-install damaged files" but it didn't find anything wrong. After that, it boots fast and boots to Windows.



Thanks
Dan