I beg to differ. Never have I ever had a keyboard do that, even the most ragged beaut up dirty keyboard. The beeps and the lights are controlled by the software, they are not hardware dependent. The keys of the keyboard do not directly control the lights.**
Also, the OP said "..When I was using Windows 7 Ultimate Edition - 32 bit I never had this problem. But then I upgraded my RAM .."
It is the RAM. Go back to the original RAM.
** To prove this yourself, take any old keyboard and plug into your USB port on the front. After a few seconds Windows will let t you used the Num Lock and Cpas Lock keys. The lamps are software controlled.