I use Onyx to keep my Macs clean and running tip-top.
http://www.boostware.com/os/mac/onyx.html
I just run the automator, it cleans the system, prebinds it, runs all cron jobs and can do a few miscellaneous things in addition.
The software restore in in the Application/Utilities folder. Use Onyx first, it may just need the cron scripts ran and a prebind to get it all back to normal.
Also, just out of curiosity, in the preference/energy saver panel, see what you processor is set to. If automatic, set it to full speed.