Are there any external devices not connected that might have been earlier? Have you added or removed and hard drives or changed any drive order in the bios?
I assume it boots normally to the Win 7 DVD? Does it find a Win 7 install? Have you run the start-up repair 3 times?
Any chance your hard drive is going bad? Some other type of corruption might be causing problems, which might be anything from a virus to overheating problems, to memory issues.
One other thing of note... the partition size that it finds the Windows 7 install on says 0MB (it is a 500GB drive in a single partition).
1. Insert your windows installation disc and restart your computer.
2. Choose your language settings, and then click next
3. Click "repair your computer."
4. you are done
Ok... boot into windows Setup. Let it load and get right up to the part where you can format the hard disk... At the bottom of the dialog you should see an icon for "More" ... if you click that you should be able to see tha partitions on your hard disk... What does it show you?