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

Brad