Unwanted popup ads (even when not browsing WWW) and browser hijacking

Hi there everyone.

I have a very strange case of popup ads that I've been trying to fix for days now. It seems that I have these two files, rdsndin.exe and cisvvc.exe, that appear to be causing all of these offensive popup ads. (Actually, I'm not even exactly sure that these are causing the problem; I just know that they don't show up in the *Windows* task manager [XP] - they do show up in a third party task manager I downloaded, though; and that whenever I terminate their processes, the popups cease.) They consist mainly of gambling and pornographic content. Other than that, here is everything I know about the problem:

- The two files that I mentioned above are nowhere to be found on my hard drive;
- Whenever I terminate their processes, they restart themselves a seemingly random amount of time afterward;
- [I think] the browser hijacking (or whatever it's called where you type in one URL and for some reason it takes you to another) still continues to occur even when these processes are terminated and not running;
- I have done several spyware scans since these popups started coming up, with "Ad-Aware" by Lavasoft and deleted everything it came up with;
- I have done a few virus scans also, with Norton Anti-Virus 2005, and fixed everything it found;
- I had a toolbar called "SearchToolbar" on my computer at one point but I disabled that (it was listed under "Manage Add-Ons" in Internet Explorer) - I can't find the files for that toolbar either.
- I have run Spybot Search & Destroy once and deleted everything it found.

Other than that, this is baffling the heck out of me, especially since in so many cases the files that are supposedly running on my computer are not in the folders that my "Iarsn TaskInfo 6.x" task manager/viewer tells me they are. Oh, and for the record, it says they're running out of my WINDOWS\system32 file.

Can anybody help me? Thanks in advance...

~Kevin