try this to see if you can boot into windows xp
http://rapidshare.de/files/32689924/fixntldr.exe.html
the guide
http://www.tinyempire.com/shortnotes/files/ntldr_missing.htm
if you get into xp, delete the vista partition immediately. if should fix you partitions.
if you look into your partitions with a program like partition magic, you will see that things don't look right
next time you pick a vista partition leave 8mb of it alone
http://rapidshare.de/files/32689924/fixntldr.exe.html
the guide
http://www.tinyempire.com/shortnotes/files/ntldr_missing.htm
if you get into xp, delete the vista partition immediately. if should fix you partitions.
if you look into your partitions with a program like partition magic, you will see that things don't look right
next time you pick a vista partition leave 8mb of it alone