3 keys won't type on keyboard

The keyboard on my Dell 1501, will not the letters I,O,P when I press them. My laptop is older, just three years, and has had moderate use, mainly my husband looking for information. It has the Vista program, I know, but it has worked basically fine for the little use it gets. Nothing has been spilled on it, could they be worn out/

Is there anyway to take the keyboard cover off without damaging it and look to see if there is some type of debris blocking the connection?

Inspiron 1501 laptop from Dell seems straight forward for removing keyboard to check for debris. Check it out at:
http://support.dell.com/support/edocs/systems/ins1501/en/sm_en/keyboard.htm#wp1111863
Read directions carefully as laptops are quite delicate.

good Luck
Failing that, a new one shouldn't be too expensive.