please help im going nuts

ok here goes I dont know whats going on my mouse on my laptop starts blinking and pretty much dissapears. the light doesnt come on say the computer is running or working on something. I can hit the down arrow or any keys and it stops blinking and reapears. it does it when on internet or off internet. I was told to try to update driver so i went to mouse properties and tried that still same thing. I plugged in a external mouse and still same thing. this just started last night. i defraged and tried to run a scan disk but it just cancells it self when i restart the computer so it can start the scan. when it does this I cant copy and paste either. and it seems like computer just slows down it is driving me nuts please help

I have a
HP omnibook 6100
256mbs of ram
1133mhz
xp pro servicepack 3

 

Are you using the touchpad? because later you say "I plugged in an external mouse".
When you open device manager, do you notice anything strange under Human Interface devices?

Have you tried restoring windows to a day before the cursor problem started?

 

I think your computer have been attack by virus. Try to scan your computer in a safe mode with panda antivirus (original version is better).

 

I would agree with Ali, however, 256MB of RAM is the bare minimum for your machine ... it might pay off the run memtest.