system
3
I would strongly suggest updating Avast and running a full system scan with security set to high and archive files checked, run a couple of scans with online scanners (such as Trend and Symantec) as backup, and you might want to run the Avast free tool as well which can deal with a number of problems not dealt with by Avast itself. Then run Spybot and Ad Aware and then Disk Cleanup and Defrag. And clean out e-mail program Sent Items and Trash. After that back your files up regularly.
Good luck! Hope you get everything back OK.