Greg's 08 MacBook Pro makes a strange noise. Now it even autotypes all by itself! Leo says it sounds like a stuck key. He should go through all the keys just to see if one of the keys is sticking a bit. It's common as keyboards get dirty.
When having an issue on a Mac, it's always a good idea to create a dummy account to see if the issue is specific to that particular user login. If the problem persists, then the issue is system wide. Next, if he has a CD or USB key with the operating system on it, he should boot to that instead and see if the problem persists. That can rule out software as the culprit.
This is why creating an image of the hard drive when everything is working properly is a good practice. That will create a "spare tire" for the computer. If something goes wrong, you can boot to that and at least have a temporary solution until you can get the real issue resolved. Super Duper from Shirt-Pocket Software is a great choice for making a bootable backup for Mac.