Possible Malware Problem

I downloaded and ran an executable from Limewire, and my computer has been having trouble since. First, I woke the next day to find explorer.exe has crashed, and it would not re-open. I went into Safe Mode, and everything worked fine. I started it in normal mode, and all these command windows started opening up and closing, most of them blank, about 30, then it stopped. It is grudgling slow; lsass.exe keeps consuming resources, and its CPU usage keeps jumping around. But explorer hasn’t crashed. It is slower than it should be under that CPU usage. I wonder if I have a virus or root kit. I ran AVG anti-virus and Ad-aware; they didn’t help. I ran Spybot, it found some registry entries for “Vutimendo” or something; but when I tried to remove them, it gave an out-of-memory error, and another error about a missing .dll. I installed some root-kit removers; neither would go pass the registry scan phase. There are no restore points. Right now, I’m running trend micro online virus scan, but it’s slow. What is my best course of action? BTW, I’m a certified technician. It is an optimized machine, though a little old, from 2003, running XP PRO SP2. What do yall recommend?