Huge,
The first thing I would do is check the keyboard. First make sure it didn't come loose from the back of the PC. If you have an extra keyboard around you may want to swap it out and see if that is the problem.
Your hard disk may also be going but this will be harder to determine. If it is only happening when you go to the Internet then try shutting off your cable modem and see if the problem clears up.
Also if all you have is the free virus scanner you should try and purchase a full version. I have Norton AntiVirus and it works fine. If you buy the full version you get a full year of updates, which ensures that you have the latest virus definitions, which you may not get with the free versions.
It's hard to troubleshoot without being in front of the computer, but if you want you can shoot me an e-mail with more detail and I will see if I can help you. [email protected]
Good luck,
Anthony.

The first thing I would do is check the keyboard. First make sure it didn't come loose from the back of the PC. If you have an extra keyboard around you may want to swap it out and see if that is the problem.
Your hard disk may also be going but this will be harder to determine. If it is only happening when you go to the Internet then try shutting off your cable modem and see if the problem clears up.
Also if all you have is the free virus scanner you should try and purchase a full version. I have Norton AntiVirus and it works fine. If you buy the full version you get a full year of updates, which ensures that you have the latest virus definitions, which you may not get with the free versions.
It's hard to troubleshoot without being in front of the computer, but if you want you can shoot me an e-mail with more detail and I will see if I can help you. [email protected]
Good luck,
Anthony.