Keyboard Dosn't Type All Letters

On my Dell Inspiron 1501 laptop I've noticed within the last week or so that whenever I try to type something that some letters don't actually get typed whenever they're pressed. I know the keys aren't sticky or anything. And I've already looked under the Device Manager for the keyboard and it said everything was working fine. I've also already tried to update my driver, but it said it was already updated.

If someone could please help me, I would really appreciate it.

Welcome
The first thing that I would try is to use a new keyboard to try and isolate the problem.
How to Add an External Keyboard to Your Laptop - For Dummies

Try with a clean boot
http://support.microsoft.com/kb/929135
If that does not work, then it is software. Try a system restore from before the problem

Make a full anti virus scan
Download and make a full scan with malwarebytes..

I don't have any other keyboards that I can try it with. :/

And my system restore will only let me go back as far as 4/27, unless there's a way to go back further?

And I'm not sure how to do a clean boot. XP

Hello Kurai, welcome to the forum.

It may be driver related so update your keyboard driver from device manager. After updating driver if it doesnt work properly just press Ctrl + alt + Insert and check.

Second thing, Most likely your keyboard is failing.Try connecting another external USB keyboard and see if you get the same problem.

Share your result.

Thanks.
Arvin

We really specialize in Vista,
In lieu of clean boot try in safe mode.

If you are sure that the drivers are updated as mentioned by you and again by Arvin. I can make a safe bet that it is the keyboard, find a way to test it. Borrow if you have to.