WinXP Installation Problem (1 Viewer)

[Geoff::L]

So I tried to update my dads winXP with SP2 tonite. When SP2 was installing it said that it ran out of space on the harddrive so I cancelled installation. Now when I try starting the computer the winxp splash screen comes up but then the computer restarts back up. It keeps doing that. It never gets past the splash screen.
Any solutions to this problem? Am I going to have to do a reformat?

 

[Geoff::L]

Never mind; problem fixed. I just put the winxp cd back in and set it to repair. There was another option for recovery but unfortunately I forgot the administrator password.
What is the difference between recovery and repair anyways?