See:
http://ubuntuforums.org/showthread.php?t=113630
Or you could delete the partition and fix the MBR using (FOR VISTA):
Bootsect.exe /NT60 c:
or
Bootrec.exe /FixMbr
Bootrec.exe /FixBoot
Bootrec.exe /ScanOs
Bootrec.exe /RebuildBcd
+
bcdedit.exe /export "C:\Boot\BCDBackup"
bcdedit.exe /import "C:\Boot\BCDBackup" -> restores the store