Hmmmm, If the MBR is the only thing you messed up.... Get a Windows XP setup disk (preferably XP Pro, but XP Home works also) Load the recovery console and use the following commands:

bootcfg /copy
bootcfg /rebuild
bootcfg /disableredirect

That will make a backup of your boot.ini file, rebuild your MBR to work with XP and then disable redirection into LILO...


Also you can just edit lilo.conf to work with XP:
http://www.tldp.org/HOWTO/MultiOS-HOWTO-6.html

If none of that works go to www.osloader.com and download OS loader, it should make it a little easier for you =)