I have a hp pavilion@ 530n w/ win xp home os

Hello, my name is norm, i had my computer worked on ,and the tech had set my computer in the safe mood and hit restart and it now just keeps looping and wont go to start up ,it was working fine before he did this .ihad put in a new ram and changed it with the old one and cant get it out of the loop or start it up normly . any ideas?