Keystrokes repeating in Snow Leopard

Hi, I'm bringing this question here in the hopes that one of our Mac users can help me fix an issue with my old Mac Pro.

I occasionally have an issue where my Mac will give me unwanted key repeats for up to 30 seconds, and was wondering if anyone else has experienced this problem?

I have noticed this problem in a number of applications, some Apple, some third party.

Noted instances have occurred in:

• DVD Player – sometimes the play/pause will get stuck and stutter olayback for an extended period.

• Safari – when typing an address into the URL bar a key may stick, giving me a URL hundreds of characters in length.

• MPlayer OS X – using the arrow keys to move through playback can cause cause playback to fast forward or rewind the playback for an extended period.

• Finder – mainly only when I notice the problem in a program and jump back to Finder, the issue continues for a period.

I have tried troubleshooting this step by doing the following:

• Restarting the Mac, this fixes the problem when it occurs, but the issue still returns later.

• PRAM/SMC resets, as above they temporarily fix the problem.

Currently i have gone into my keyboard preferences and set "Key Repeat Rate" to slow and "Delay Until Repeat" to long in the hope that this may help.

However, is there a way to set Key Repeat Rate to "Off", to stop unwanted key repeats?