xp pro machine won't boot

Ok yesterday I changed the name of this computer in winxp and it was working jsut fine. Now I cant get this thing to boot at all. wont boot even in safe mode......I get a split second blue screen (almost unnoticable) and then it restarts.....what to do????? should I try a repair from the XP disk?

thanks

Yes try that.... tell us what happens...

I first tried the last known good and that didnt work.

I have never used the recovery console B4 but it asked which install to do I chose 1 because its the only one and then it asks for an admin password. I know I didn't password protect the admin account on this machine but it just goes to the C: prompt when I leave it blank and press return. WHat do I do next or what am I doing wrong??? thanks

Don't go to the recovery console just yet. Do the quick repair first.

how do I do the quick repair...

It didnt give me that option. Instead of hitting recovery console when I booted with the xp pro cd I hit enter to set up the hard drive and it didn't have a quick repair option there either..........any suggestions?