Bad video card, maybe?
Try these steps.
With a fresh reboot, give your PC about 5 minutes to arrive at the login screen. OF course, you won't see it, but you can attempt to login blind.
I'll assume you're on Windows XP, and that your login remembers the last login name. If this is true, then the prompt will be focused in the password field. Type the password (you'll be blind, so do it slowly). If you feel you've made a typo, simply hit the backspace key about 12-15 times to back up over the entire password.
Hit the ENTER key after you've typed your password.
If your sound is not muted, and you still have a sound play after login, you should hear it after you hit the ENTER key.
Wait for a minute or two while the startup applications completely load. Then, (another assumption here) hit your WINDOWS key once - it's often between the CTRL and ALT keys.
Hit the letter "U". This chooses SHUT DOWN in the Start menu you launched when you hit the windows key.
Hit the ENTER key to shut your computer down.
All this will tell you is that you've got a bad monitor, or a bad video card. I suspect your monitor died.
In most cases, if your video card was bad your system would beep at you and not boot.
It is tempting to think that you can "fix" by asking here for help, but if you don't know any more than you indicate about the hardware, then bite the bullet, take the system to a local, well-known repair shop, and let them fix it.
If you didn't know how to change the oil in your car, you wouldn't be posting here asking for help. You'd just take it to someone who did know. If you have a rash, you'll probably want to have it looked at by a doctor. If you have a computer problem beyond your capabilities, take it to a legitimate repair shop. They're worth the money just for the diagnosis time.
Plus, you're helping keep them in business for the next time when you **really** have problems.
As I pulled in there were 2 urgent messages (medical emergency in family), so I literally dumped it off and ran....but later got a message that the monitor had taken a shiite; therefore I don't yet have the particulars. He gets to sell me a new one tomorrow, but that's fine with me.
Thanks again, all.