Windows 7 - Windows 7 Ult 32b boot failure; system repair unable to find install

In an attempt to remove a virus, I made some changes to my registry (after saving a backup of it) using CCleaner. Upon restart, my computer failed to boot; the windows logo appeared for a few seconds, as usual, then a blue error screen flashed, and before I could read it the system restarted. Now it boots to a prompt to either boot normally or perform system repair. Booting normally causes the same boot failure mentioned above; I located a windows 7 32bit repair disc and restarted the system, pressing a key when prompted to boot from disc. However, the automatic system repair was unable to locate any system restore points, nor even a windows installation upon which to perform the automatic repair.

I have a separate hard drive installed that can boot into Ubuntu using the grub boot manager, and using ubuntu I can navigate the files on the windows 7 hard drive, including the registry backup that I made. Does anyone have advice for repairing my system?

A little more information; the automatic repair attempts a series of tests that exit with error code 0x0 (no error). It then says that the "Root cause found: System volume on disc is corrupt" It attempts to perform File System repair(chkdsk), but that fails, Error code 0x1f.

The hard drive Windows 7 is installed on is a Seagate Barracuda 7200rpm 500gb,

Repair Install
How to Do a Repair Install to Fix Windows 7

Thanks, but that doesn't help. Like I said, I am unable to boot into windows 7, and that repair strategy can only be run from within windows 7. Still looking for a solution. How can I make the repair find my windows installation?

Same problem here... Any suggestions. Normally I would restore my pc via a netowork connection but all it will do is just cycle in an out of those screens asking to Boot normally or do system repair (recommended)