Thanks for your help everyone. I'll remove the quicktime and nero processes to see if those help, and I'll defrag the hard drive once I get some down time. I'll also take a look at some of the HijackThis tutorials so I can identify suspicious processes in the future.

As an aside, while researching the problem I came across a site that appears to have a database for a lot of the common processes out there and provides descriptions as to their function:

http://www.kephyr.com/filedb/index.php

Their bazooka adware and spyware scanner is intriguing, and their database (at least from the entries I typed in) appears to be on the level. Has anyone had any luck with this site?