Do not use alcoholic cleaners, they do not work well for the exterior of your cleaner. It will not be cleaned well by alcohol cleaners, so don't waste your time, or your money buying these to clean a computer.

To clean the casing use a cloth that has been dipped in your hard surface cleaner solution, then make sure it is well wrung out. Then wipe your rag over the casing and any external parts of the computer. This includes everything from the cabling, to the base of the keyboard. Get everything, dust can ruin little parts too. Then, rinse the cloth out. You want to make sure your rag is only damp, excess water can cause problems with your computer, an short it out etc. So, do not force your rag down into the vents or slits in your computer.

The next thing you want to clean is the computer keyboard. You want to make sure you do not use any excess water on the keyboard keys. If you do you will short them out. You will want to clean your key board using little bits of damp cloth pushed around the keys with toothpicks. Then on a regular basis, use an air can to blow air around and get rid of dust.

If you want to clean your computer properly, do the following every six months:

 Open the case. You will want to unscrew the backing and take a vacuum cleaner to it. Use a the crevice tool. When you use the vacuum, be extremely careful how you do it. If you remove all the dust out of the case and the fans you won't have as many problems with your computer. Make sure you are grounded when doing this so that you do not short out your computer from a friction shock. You will also want to keep the motor of your vacuum away from your computer.

 Vacuum the vents around the casing and the keyboard. A lot of dust can collect in the keyboard, and this can settle down and short it out and cause other problems. Keeping your computer as free from dust as possible will keep it from overheating and thus from damaging its components. It is really easy to run a vacuum, takes little time, and no real money. But replacing ruined components or a whole new computer is pricey.
To clean your mouse, remove the ball and wipe it clean to get rid of dust. You will want to clean everything around the rollers away, so that you do not get it clogged up with hair or food, or whatever. Make sure you do not use water to do this, and if necessary, scrape residue out, then reinsert the ball.

Taking time to properly clean your computer on a regular basis will save you heart ache, head ache, and time. You will be less likely to suffer the frustration of malfunctioning computers, lost files, photos, etc. Instead your computer will function better for longer.