Have a read of the trouble shooting section assuming you get a grub menu?
http://www.linuxquestions.org/questi...hlight=trouble
2) assuming you had resized xp to make room for rh on the same drive your C drive is (hd0,0)
You will need to use the TAB key if its not and re-read the trouble shooter but jumping ahead try this first
boot goes to grub and it hangs or does nothing
Press C for commands and prompt or cursor changes to show grub
then type
unhide (hd0,0)
rootnoverify (hd0,0)
makeactive
chainloader +1
boot
pressing enter for each line.
3) print this out b4 reboot and print out the trouble shooting section in case you need to use tab if c drive is not hd0,0
4) You could always use your xp cd to try rescue. Windows forums or windows site should tell you how. You will need to resolve your md5sum issues b4 trying linux and I suggest you put ntldr back on soon otherwise you will be peeved off with linux.
5) try the readme files on various linux cds b4 installing. I have been burnt myself so it is handy to know