Windows 7 Error Loading NTLDR

download The Ultimate Boot CD, burn to a disk and boot from TUB CDand wipe the drive, then reinstall W7

you should just be able to reinstall you os with out downloading anything..

When you upgraded to Win7 was your previous OS on the same drive as Win7? Were you running a dual boot system with Win7 and WinXP or Vista?

Have you tried using the "bootsect /nt60 all /force" command from the Windows Repair Console? There is a write up about how to use this command here http://technet.microsoft.com/en-us/library/cc749177(WS.10).aspx

This command should reset your system to use the bootmgr for Win7 instead of looking for the ntlrd used by WinXP.
http://technet.microsoft.com/en-us/library/cc709667(WS.10).aspx also has a BCD rebuild command that you may have to try.