Windows 7 - Pc usage goes to 100?

Ok so my computer is acting up , at first i thought it was a ram issue , but when i am only use 1 gb of ram ( i have 2 gb) my cpu usage goes to 100 then drops to 30 then back to 60 and so on , even on start up it goes to around 50% without anything opened. So i tick the show all process on my task manger and i see alot of svchost , more than 6 running, should i be worried, i heard some of them could be a virus and i also MsMpeng.exe running and it uses 50,000 usage, it uses more memory than google chrome.
So my question is how do i fix this ??? both svchost and MsMpeng.exe worries me , iknow svchost is safe but it also good be a virus.
Any help on these would be greatly appreciated.
Im running windows 7 32 bit.

MsMpeng.exe here use 45MB. For svchost,I have 11 of them.
Download and run Process Explorer,to see more info about processes.
Also update your system specs.
How to - System Specs

my one uses around 52 mb and i have around that amounts of svchost but one uses around 32 mb, still need a fix for these

Hello Ringo, please follow Boshko's advice and fully update your system spec using the tutorials he provided? That would help us a lot in getting to the problem.... if there is one.
I must say I'm not surprised or worried with Windows 7 32b using 1G of your total 2G's. Is it causing a problem or are you just worried because you saw the mem usage?

i will do that and yes i do get worried a little bit when my cpu usage jump to 100 and the back to 30 and so on.

thanks for the help

WIN | type RESMON | ENTER |

WIN is the key with Microsoft flag on top.

The CPU tab and the MEMORY tab may be of interest to you.