What does it mean if your keyboard and mouse just stop working on your

It could be that your motherboard is failing.
How old is your computer?

It's close to 10 years old, but I had it cleaned out of junk that was bogging it down. It locked up so I even had some things replaced like the ram was increased. I noticed since all of this stuff started happening that when I go to star up the computer, the black screen before the log windows xp log in a long white bar scrolls across the bottom of the screen. I haven't seen that until the mouse and keyboard stopped working. I don't think that it could be a virus because the Internet use is limited on that computer. They are not wireless and I don't use the USB drives for them. It's the round housing with the pins inside. Maybe this info will help but I'm wondering if I need to run an install disk for those drives. If I do that though I might need the use of the mouse. I tried to use a wireless mouse but nothing happened, probably because I hVe to set it up first.

If it's that old maybe it's time to get a new motherboard.
If your main concern is to get your paper off that computer you could install the hard drive in a different machine as a slave and save all your important files while you troubleshoot and fix your current system.