winXP computer doesnt boot up.

[shashgo]

It was okay this morning andit was working fine although very slow.  I installed an antivirus on the computer (avira) and then shut it down to restart it.  It doesnt boot up now, all I get when the computer starts is the initial windows XP splash screen with the logo and then it goes away and I have a black screen with a blinking cursor in the top left.  And when I shut it down again and restarted it after that, I went through the splash screen and then some windows writing showed up followed by the words "keyboard failure".  I disconnected the keyboard and it still says "Keyboard failure" when I restart.  Weird. 

I cant even get to safe mode by pressing f8.  What doI do

[DaveLembke]

Is it possible that this system may have been experiencing a hardware failure that caused the performance loss and now it has reached its critical point of serious failure.

Is this keyboard a standard PS2 type or USB, and what was the nature of this system leading up to this point? How old is this computermake/model and how much ram, and did you make any hardware changes or upgrades to it recently?