Strange shift key problem

i would use better grammar, but it is hard to type when both your shift keys appear to have been rewired.

I have an inspiron e1505 laptop, a couple years old. About a month ago, while playing a game, something strange happened - my shift keys stopped hitting shift. now they hit a weird combination of buttons, with the left shift key triggering 3 or 4 different keys at once - including caps lock - and the right one also triggering 3 or 4 different keys. I just hit the right shift key and these buttons were pressed: m,.\
XCZ

hitting the left shift key hits a bunch of buttons that even more random.

I plugged in a usb keyboard and that worked. So I bought a replacement keyboard and installed it. It didn't work. So I tried defragging, using cc cleaner, running malwarebyte's anti-malware. Still no luck. So I took the plunge, bought windows 7 and installed it on my computer. STILL NO LUCK.

which makes me think that some evil / brilliant program i might have accidentally downloaded simply took my shift keys and linked - i can't think of another term - to different keys. how would i go about relinking them to being shift keys? Using the on-screen keyboard is kind of depressing all the time. ANY advice or help would be MUCH appreciated.

A possible hint, but i doubt it's usefulness - an it friend suggested that my shift keys are also connected to the right and left mouse keys. i dont know how true it is, but it just might be.