Need Help - Keyboard Randomly Freezing

Okay, here's the deal. I'm using a Dell Inspiron 1545 Laptop running Windows Vista Home Premium, which I have owned since the end of last August. While I am typing, the keyboard will randomly freeze/stop working. It unfreezes a few seconds later, allows me to type normally, then does it again. The problem varies, as sometimes, only one key won't be typed versus times where it is completely unresponsive for fifteen seconds at least. The rest of the computer operates normally. I have run AVG scans and they come up clean, and am currently updating the computer OS. I have a theory that the shift and backspace key may be making things worse, but i'm not entirely sure. Any possible solutions to this problem?

Thanks.