Follow this Windows 7 installation tutorial to clear all your partitions and start over again:
You will need to backup all your important data first. If you can't boot into Windows now, you can use your Windows 7 install DVD or USB to backup it, use this instructions:
Open DISK MANAGER and post a picture of what it shows please.
If you can't do that, you'll need to use the COMMAND LINE from the Install media.
Then enter these commands :
SELECT DISK 0
Copy the results in a reply. That will tell us what we're looking at.