Shift And Ctrl Key MalFunctioning ?

Brief Question : The Question is Simple
when i press my Right hand side ctrl key [ 2 SHIFT + 2 CTRL ] keys getting pressed
same thing with Right hand side Shift key as well but left hand side keys are functioning properly.

Note : when i press CTRL key in on-screen keyboard using mouse everything works normal, but when i press from physical keyboard problem is coming i tried to replace the keyboard but same problem with new keyboard as well i suspect this issue with windows itself. i wonder there is no answer in Google for this !!
i suspect this problem is occurring since 1 Month and more. and before that it was functioning properly..

Operating System : Windows 7
Mother Board : Core 2 Quad
Ram : 5 GB (3 GB Usable)
32 Bit Operating System

if you need more information please do let me know !!!

Thanks & Regards

Raviteja Adepu