I don't use this computer on the internet....Worked great for a couple of weeks, the keyboard and mouse often stop working now and I have to hold the power button to shut off. Then it won't reboot - just a black screen. The red light on the front of the computer stays on - there is no beep when it starts. I use XP.....Any ideas? Thanks....

The whole thing together screams dead/dying motherboard. but that's just a halfway educated guess. Do you happen to have a USB-PS2 adapter on your keyboard and mouse? and can plug them into USB slots instead of the PS2 ports?
One of my kids pulled my keyboard out the hard way one time and broke off a pin inside my PS2 port on an old computer, caused all sorts of crazy problems.

And when you start it up does it ever get into your OS? Does the black screen thing only happen on a hard reset? And when it is on the black screen bootup do your fans and HDD kick on? I'm assuming the red light you're talking about is your HDD but ya never know...