Are you having problem booting your WUBI installation because the drive seems corrupted?
There could be a solution -- the Ubuntu CD.
No, we are not going to reformat and reinstall everything. Continue reading.
Let's say you installed Ubuntu (WUBI) on your drive C: with drive label, MyDrive.
Step 1. Load Ubuntu CD in your CD-ROM and boot from it.
Step 2. Choose, "Try Ubuntu without any change to your computer" and continue booting.
Step 3. Once Ubuntu has fully loaded, go to Places -> Computer.
Step 4. A window will open and you should be able to find MyDrive (the drive C:) listed among File System, etc.
You are not done yet.
These last steps are crucial.
You need to have another partition with file system readable by Windows -- it should be non-EXT2/3 format.
Via Another Partition:
Step 5. In your MyDrive, copy WUBILDR and WUBILDR.MBR and paste it to the other partition.
Step 6. Shutdown Ubuntu and removethe Ubuntu CD from your CD-ROM.
Step 7: If you are in luck, your Ubuntu should install just fine.
If not, having a bootable external disk could also be handy.
Let's go back to step 5.
Via External Hard Disk:
Step 5. In your MyDrive, copy WUBILDR and WUBILDR.MBR and paste it to the external hard disk.
Step 6. Shutdown Ubuntu and remove the Ubuntu CD from your CD-ROM.
Step 7. Make sure that the external disk is plugged into your computer before booting. If you are in luck, your Ubuntu should install just fine.
If you get your Ubuntu back booting again, my congratulations! But the bad news: Your Windows installation will still be unbootable :D