1) Create a Restore Point using System Restore
2) Create a Repair disc by going to Start...All Programs...Maintenance...Create a System Repair Disc
3) Test the System Repair disc to make sure that you can get to the System Restore entry when you boot from the disk (you may also want to try actually using System Restore to make sure that it works)
4) Download this free program (
Autoruns) and use it to disable any instances of PS2.sys that are starting (DO NOT DELETE - only disabled by removing the checkmark in the left hand column)
5) Check in Device Manager (to include showing hidden devices from the View menu item) and ensure that any instances of PS2.sys are "Un-installed" (DO NOT DISABLE THESE).
6) Check in the Services applet (services.msc) to be sure any instances of PS2.sys are disabled.
7) Go to C:\Windows\System32\drivers and rename the PS2.sys driver to PS2.BAD
In the event that the system doesn't boot:
1) Boot from the System Repair disc and use the Command Prompt option to rename PS2.BAD to PS2.sys
2) Boot from the System Repair disc and use the System Restore option to restore the system to a point before the changes were made.
Good luck!