There is obviously something wrong with the bootmgr/active partition. For Win7 there should be a 100MB active partition (unless you installed into a predefined active partition).
You can inspect all of that with the bootable CD of Partition Wizard
(the link is on the left side of the webpage). See whether there is a 100MB partition and whether it is active.
If you want to reinstall an 11th time, predefine a partition on the HDD with these commands. You find Command Prompt on the installation DVD.
Select disk n (probably 1 in your case)
Create partition primary
Format fs=ntfs quick
Then install win7 into that partition.