When ever i start up xp pro a command box comes up in which shutdown is written and the computer immediately shuts down, i can only get on to my pc in safe mode, i assumed this was a virus and have tried norton, microsoft anti spyware, spy doctor, registry mechanic and still no luck! could any one please help??

First try a HijackThis log in our HijackThis section. If that doesn't help then return to this thread.

Please follow the instructions HERE & then post your log in a new thread in the Spyware, Adware, Viruses and HijackThis Logs section.
(Not in this section please).