If it were mine, I would go find a friend or head to office depot and ask permission ..
Make a System Repair Disc, from control panels Backup and Restore.. on any computer with matching win7 64bit
Boot from that DVD
Run StartUp Repair 3 times without letting it boot back into windows between each run - 1st time you run it it may take 20 or 30 min, but 2nd and 3rd times its just a minute or so. It will check and repair more things each time apparently and at the end of the third time it will correctly, in windows style, rebuild your mbr / partition tables. I think it even will run SFC... but if you still cant boot... Run SFC /offline.. pay attention to paths, its not normal computer paths when booting from dvd.