Number keys on right side not working

Hello, I recieved my Dell Studio Laptop about 2 months ago, everything worked fine at the time. I was wiping off my keyboard one day and all of the sudden the number keys on the right hand side of the keyboard stopped working. I have tried the NumLock key and that did nothing. Most of the time it does nothing, but sometime is will make the page on the screen jump around, like if it were the arrow keys. I chatted with the dell people on line and they told me that it was a faulty keyboard, to send it into them and they will replace it. I just got it back the other day, and nothing is different!! They either did not replace it or that was not the case at all. They didn't even try it out. I am very discouraged, please help me!!! Thanks a bunch!