I gave you the steps required to convert C to Primary first so it will accept the Active flag and then write the System boot files to C. You are correct that this cannot be done to a Logical partition until it is converted.
If you can boot into an OS now you should be able to do these operations from the Partition Wizard Home Edition however it is safest to have the CD for rescue purposes, and you need the Windows 7 DVD or
System Repair Disk anyway to run the required repairs to write the System Boot files to C.