Do not wipe the HD if you don't want to delete all data.
Please post back a screenshot of the maxmimized Disk Mgmt drive map with listings now that you have made the changes, using SNipping TOol in Start Menu.
You likely didn't format C (or it failed) as it holds the System Boot files and wouldn't boot WIn7 without it. As explained and ignored, Win7 cannot boot from its own partition because it is part of a Logical Extended partition. And you cannot convert it to Primary partition (which can boot) without deleting the other sub-partitions which hold your data.
You cannot change the drive letter for installed Win7 - it will always ruin the OS.
Your best bet is to do a partition-specific wipe of C with Partition Wizard boot CD, then reinstall Win7 to C and gradually transition all programs from I to C. Then you can delete I and use the Logical Extended partition exclusively for data as it's intended.
You should tell your Dad that no data is safe unless backed up to an external HD, so he will buy one, you can transfer your data off, wipe the entire HD and clean reinstall Win7.