boot problem

Hi all

I am new to linux but it is a fantastic OS

I have a small problem with sled 10.1

I decided to load xen onto it it installed fine then it ask me to reboot and choose the xen option on boot which I did and the system started up but just sat there with a blank screen with the mouse use only

I then rebooted after it failed to load the login screen and went to boot normally into sled which froze and dropped me back to loading screen

I then rebooted with the boot cd and did an auto repair on the system and on reboot it now fails saying checking internal tree failed then stops

Can someone help