shouldn't stop WindowsXP from starting up. It will simply load a generic mouse driver.
I'm not sure why your friend is pressing Ctrl/Alt/Delete - he can start Windows in safe mode by pressing F8 as the computer does its POST (Power On Self Test). That should present him with the option he needs. Once he's into Windows he can remove the driver which he thinks is causing the problem, and them restart the computer. As soon as he gets a good boot he should create a restore point.