I would try disabling the anti virus program you have now; then run the Bitdefender version or bull guard version
scan with those, often times any AV program can miss a virus
http://www.bitdefender.com/site/Down...tionVersion/1/
http://www.bullguard.com/download.aspx
I would try the bullguard first.
post back with your results
the memory testing program you spoke of can be found it my signature links (memtest86.com = free)
also; it wouldnt hurt to download and run your hard drive manufacturers diagnostic utility against your drive. it will be westerndigital, maxtor or seagate etc etc etc not any dell utilites