CPU Usage Flaw or Memory Leak

Hello,

I am experiencing a strange memory leak or CPU flaw where my CPU usage randomly shoots up to 90-100% even when no applications or programs are open. This can happen anytime from immediately after a fresh restart or after several hours of the computer running. I have read some threads about people having similar issues, however what they described was quite different from what I am experiencing because it does not appear as if a process under Task Manager is causing it. I also tried many of the solutions that users on the forum have posted such as disabling indexing within my hard drive, but unfortunately, it has not helped the issue to become resolved at all. I just recently purchased my computer, which is a Dell laptop, in September 2009. When I bought it, it came with Vista and later I upgraded to 7.

Specs:
Processor - Intel Core 2 Duo T9900 @ 3.06 GHz
RAM - 4.00 GB
System type - Windows 7 64 bit
Display - ATI Mobility Radeon HD 4670

I would appreciate any help on this matter. Thank you.

Does the usage stay at 90-100% for long periods? Several minutes?

Is this a stock install of Windows 7 from Dell? Along with all of Dell's preinstalled software?

Well it was Vista then I upgraded to 7 from Vista. I don't believe I had any software on my computer when I first got it.

Edit: I did have Dell's preinstalled software such as Dell DataSafe Online, Dell WebCam Central, and all that.

Any help would be appreciated.

Windows Media Player Network Sharing Service is often a culprit for this.

Open Start menu, type services.msc and press "enter".

Go down to Windows Media Player Network Sharing Service and double click on it and Stop it and then disable it.

It's used for when you transfer media between your Xbox 360 and your PC, so if you do use a 360 for this, then set the service to "manual" if you want.