Problem with windows xp

im not sure where i should be directing this but just this afternoon i was on my computer and my mouse started to act all funky and it was like i had no control so i restarted my computer to find two messages one saying something about a power problem with a battery and then another saying "NTLDR is missing" could someone please help me im thinking im going to have to do a system restore any help on this would be greatly appreciated. thanks