task manager shows system idle process using 90% or more of my CPU at all times - i've reinstalled my os, uninstalled every non-critical application, run system restore, run through registry setting with regcleaner and registry mechanic, installed/ran/uninstalled three different virusscans, run several malware apps (spybot, hijackthis, adaware), and manually walked through the entire hard drive for anything that might strike a layman as out-of-the-ordinary. system monitor utilities show that my cpu usage isn't what the taskmanager is showing me, but then again i wasn't able to get any two of them to agree either. possibly unrelated: i had task manager open once when launching photoshop, and saw it's use spike to 90+, while system process dropped, then they slowly (over the next 10 seconds, i'd say) switched.
also probably unrelated, but annoying and worth mentioning: i can't get explorer to reuse windows. start > my computer > tools > folder options > open each folder in the same window is selected for every folder, but they just don't.
thanks in advance for any insight.