Comma symbol keeps typing NON-STOP

Question

This is odd. The "," symbol is typing non-stop. The comma key is not depressed. It works fine and is not sticking in anyway. Nothing is stuck underneath it either. If I open any application, it will create pages and pages of ",,,,,,,,,,,,," without me touching anything. If I open something that can not type right away (ie. Mail), it makes default noise when you press a wrong key. The noise comes as fast as the commas would type, as though someone is hitting the comma key as fast as a humanly possible. Keyboard was replace just last year.
Macbook Pro, 17",
Snow Leopard
(I believe 10.6.6 - can't turn on my computer to check).
I tried a restart. I tried cleaning my keyboard. Any other suggestions? My Apple Care has run out on this laptop.
TIA. I greatly appreciate your help.
Stephanie

Answer 1

Hi Stephanie,
First try a PRAM reset and SMC reset.
In some cases, the battery can interfere with a cable between it and the inside of the MBP, causing keyboard and/or trackpad issues. Shut down the MBP, disconnect the power adapter, remove the battery, take a piece of something semi-soft (like a paper napkin folded over a couple times), place it over the cable you see in the battery compartment, and tape it down. Replace the battery and see how things go. If this works, you'll eventually want to replace the keyboard/trackpad cable (about $25 if you can do the work yourself). Note that if you go to a repair shop, they usually want to replace the entire top case assembly, which is much more costly.
If the issue persists, shut down, disconnect the power adapter, remove the battery, connect the power adapter, boot the MBP and see if the issue persists without the battery in place (but remember to save a lot, because if the power adapter gets pulled out the MBP will immediately shut down and any unsaved work will be lost).
Also look at the battery to see if it has any signs of deformity/bulging, in which case do not use it again (it may be pushing on the keyboard/trackpad cable and causing the issue); it must be replaced.
Message was edited by: tjk