If you're interested in creating music, there are even sound cards in which you can plug a keyboard. Once you have an idea of what you want the computer to do, you should be able to find a computer store in your area that's willing to work around your needs. Taking a PC savvy friend along when you pick out your new PC can also be very helpful. It will play mp3 files, wav sound files, cd's and more. It's easy to install and easy to use.
Dust removal is good.
Your PC, like the rest of your house, gets dusty. If enough of that dust builds up it can affect how well you PC runs. The simplest way to clean it is with a can of compressed air. These are available at any electronics store, computer store, or places like Wal-mart. If you're comfortable removing the case from you PC, you can use the compressed air to get rid of the dust inside.