Solve Task Manager Displaying Only One CPU

Notebook: Toshiba L645 1112x
CPU        : Core i3
RAM       : 2Gb
OS          : Windows 7 Home Premium

okay.. I've got a problem with my notebook, I think it began when I instal ubuntu and win7HP in dual boot.
it was get stuck every seccond, then I check my task manager..

click to enlarge

OMG!! what a failure is it?? the task manager displaying only one CPU working to handle that all shit task.
it's seems gonna blew up I think.. hahaha.. just kidding..

then I try to solve it my self, because when I try to google this there's just some advice to reinstall windows, update the BIOS, reset the BIOS and what ever there every one said with that. My mind just rolling and got some trust.. don't ever judge a computer problem with a reinstalling OS or even playing with BIOS. Maybe it's become a fatall when done uncarefully..