My Mouse is stuck in the upper left corn

[julienguyard]

I tried to change the mouse, but it didn't resolve the problem.
I'm on mac 10.5 and tried to reboot from the install disk but it didn't give me back the hand on my mouse
I also tried to boot on install disk 10.6

 

[midijeep]

1. Restart your computer while holding down the keys Command+Option+P+R.

2. Wait for your computer to chime twice before releasing the keys.

The screen will flash when the PRAM resets.