Strange issue: While typing, missing letters (Vista on ThinkPad)

[loudaccord]

When typing, very randomly, it doesn't register that I hit a letter. Even when I type one letter at a time very slow I might have to push the letter 2 times for it to display. It's almost like the computer is thinking but that doesn't seem to be the case. I tried using an external keybord and it isn't helping.

This is on a T43p IBM ThinkPad running Windows Vista. Any ideas?

 

[KSoD]

Have you gotten all the Windows updates and checked the IBM site for all the ThinkPad updates?