Cpu goes to 100% upon each new task

Hi

I recently ran in to some CPU problems. Whenever i launched a new application, be it notepad, ie, opening a picture, playing back mp3, whatever, the total CPU always goes to 100%, with a huge portion of it being used by the most recently opened application. Also, processes that change constanly like Process Explorer will take up 20% of my cpu constantly. I have a E6850 so this can't be right? So i started doing some serious pc maintanance/cleaning using the wonderful guide

I ran everything as requested and it all went fine and came back clean except for Combo-fix.
I had an error while running that which made my comp reboot. I managed to read something about: catchme.sys and then it rebooted, after that Combo-fix wasn't running anymore and from the tutorial i think it ought to have?

Next i ran MGTools to complete the scan and so i'd have something to upload with this post. Everything else i ran came back clean and CF didn't seem to have produced any log(s?)
While MGTools was running i had a weird windows error about: SteelwerX WhoAmI crashing... (swwhoami.exe)

Additional info:

When i first noticed my comp was slowing down i tried to rollback using system restore but found that there were no restore points, even though my comp was set to create them...

 

Problem solved:

Power options were somehow altered, limiting CPU usage to 50%, cause of this is unknown but i've set the option back to 100% and now everything is as it should be.

 

Well,

I had a lot of problems in the beginning where Vista wouldn't go to sleep. Even now i can't let steam run on this comp all the time because somehow steam prevents it from going to sleep. Therefore i have changed the Power Saver plan settings in the past.

Now when you go to your Power Plans and then press "Change Plan Settings" and then go to "Change advanced power settings" you'll get all the options for your current power plan.
One of these is named: Processor power management. Here you can set a minimum and maximum processor state. Somehow my maximum processor state was capped at 50%.
Setting this option back to 100% made my comp go from looking and sounding like a cripple pentium III to being the badass gamebeast it should be.

Now the tricky part is that i don't remember setting this to 50%, i don't even remember selecting the Power Saver plan as my default as i have my own custom power plan made. I think that this must've happened shortly after i updated my Vista to SP1.
They seem to have made a few power option changes there because i remember that there were a lot more options (like setting which components could keep your comp awake). Anyways, what set the limit there at 50% isn't clear to me, maybe it's like that per default. All i know is that setting the max under 100% greatly decreases cpu performance and leaves you with a cripple comp without it ever showing up anywhere. (as far as i know)

I hope this is a clear enough explanation