My only suggestion is to test for spyware. Dell has a spyware forum that may be able to help you.

There's malware that hides by creating files with random names which is what you appear to be getting. For example:

http://sarc.com/avcenter/venc/data/adware.istbar.b.html

You may need to download free hijackthis and post the entire log on that forum for help removing whatever it is.

Ron