Ultimate Boot CD

hi,
my pc is looping on startup,
it gets to the windows xp banner with the scrolling blue thing along the bottom
and then reboots back to the HP banner at the start

i have downloaded UBCD, burned it onto a cd, and have put it on the looping pc,

i am at the screen when it lists options such as:

mainboard tools,
hard disk tools
filesystem tools

etc.

and i am not sure what to do from here to get my pc to run normal and break this loop

any and all help is greatly appreciated

-osiris