Windows 7

Will use a 64 key on a 32 bit install and vice versa.

To disable Services use this command

start>run>services.msc

Unable to cancel Print job

Quick-n-simple fix

Click Start - Run
Type CMD - hit Enter
Type NET STOP SPOOLER
Goto C:\Windows (or WinNT) \System32\Spool\Printers
The files in there are your stuck print jobs - delete all of them
Back in your CMD window type NET START SPOOLER

Done.