If you removed all the partitions when installing Windows 7 then the odds are slim that you will be able to get it back without recreating them.
When you went through the reinstall process did you delete any of the partitions?
I would recommend creating a Hirens Boot CD
and utilize some of the options available to attempt to resolve your issue.
Unfortunately, there is a strong chance you may not be able to get anything back at all using the partition tools with the Hirens CD but its definitely worth a shot.