HELP!!!!!!!!Laptop certain keys stop work!!!

Clarifications

I have a dell inspiron 2650 and several of the keys quit working as you describe. I searched google and found that the problem was a common issue among several of the dell laptop models. I could use the laptop with a usb keyboard connected to it, but the only way to restore the functionality to the keys was to repair it. Since mine was not under warranty, I searched for a replacement keyboard on ebay. I found a new 'genuine dell' keyboard for $30 inc. shipping. I took my laptop apart and installed the new keyboard and it has been working well ever since. I was not very hard to replace the keyboard, but there was many small screws and it took a couple of hours.

Most likely either the keyboard itself has failed, or the ribbon cable that connects the keyboard to the system board has come loose.

On most laptops, there are three screws underneath which hold on the keyboard, then the ribbon cable can be inspected and re-seated if necessary (or the whole keyboard assembly replaced).