Help :(

I WAS RUNNING SOME SPRING CLEANERS ON MY PC YESTURDAY AND TRYING TO LEAN IT OUT AND GET RID OF SOME OF THE JUNK FILES AND WHEN I WAS DONE I DEFRAGED MY DRIVE THEN REBOOTED.WELL WHEN I REBOOTED IT WONT REBOOT AND WAT REBOOT FROM MY RESCUE DISK OR MY WIN XP DISK AND NOT SURE WHAT THE MESSAGE IS AND HOW TO FIX IT?
IT IS TELLING ME THE "NTLDR IS MISSING"?
CAN ANYONE HELP ME WITH THIS AS THIS IS A NEW PROBLEM FOR ME?
I KNOW I MUST HAVE DELETED SOMETHING I SHOULDNT HAVE BUT WHAT?AND HOW DO I FIX THIS?
THANK YOU IN ADVANCE FOR ANY ASSISTANCE YOU MIGHT BE ABLE TO GIVE.

 

NTLDR = NT boot loader
basically means it's starting to boot to a win NT/2k/xp/2k3 partition
then realising that it's not installed on that partition
usually no NTLDR is attempting to boot to wrong partition or sometimes a virus..
go into your BIOS and boot to HDD first