virus still there after format

Very recently I formatted one of my computers because it was over run with spyware and viruses and I was too lazy to scan and delete them. Before I formatted the computer was running at 100% CPU usage. I finished formating and everything was working fine. I was at 2% CPU usage and it was looking good. A few hours later it was up to 50%, then back to 100%. I dont know why it is still messed up even after a format. I have avast installed and it picked up a virus when I performed a boot time scan. I deleted it and the computer is still at 100% CPU usage. I also scanned for adware and spyware and found nothing. Why did the virus come back and how do I make the computer go back to the normal CPU usage? Thanks

 

Have you used any floppies?

Copied data from somewhere that may be infected?

Connected to a network? Checked your email before installing Avast?

 

Did you connect to the net after formatting? -BEFORE installing an AntiVirus? -there are a few Viruses out there that can infect a computer (that's connected to the net) within minutes of connecting.
-522.

 

Make sure you also have a firewall installed. A couple from MG library.

Sygate Personal Firewall http://www.majorgeeks.com/download3356.html
Zone Alarm http://www.majorgeeks.com/download.php?det=388

I use ZA but others recommend Sygate. Your choice. Bazza

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especially if it's windows 2000 / XP and has no service packs on it with the hotfixes specifically for Sasser and MSBlast etc.

 

ohhh! I am an idiot! I should have known that...
lol, I connected to the internet right away before intalling avast (i had avast on a cd), and I did not download any service packs...wow. Do you guys think I should reformat and start over? Like do everything right the first time instead of trying to fix it this time?

 

If you aren't too far into the whole reinstall process it wouldn't hurt to reformat -give you a nice starting point, in fact.
If you've spent some time and effort on this install then I would try and kill off whatever bugs you have (and it *can* be done).
Some people think of reformatting as giving up -while others see it as a fresh start (like having a really long shower where you scrub, scrub, scrub, lol) -it's up to you. Personally I have no problem with formatting every now and then -I like how methodical it can be... and love the fresh out of the shower feel .
You decide what's best for you..
Yours,
522.