Need to Fix W7 OS Install. How to Proceed???????????????????

[Bánh mì]

I think my W7 OS is hosed for a lack of a better way to describe the situation.
Here's the background:
*x201 shipped with W764 Pro
*I upgraded to W764 Ultimate. Have SP1 installed.
*Running BitLocker TPM+PIN
*Paritioned HDD into 120GB for the OS. Other paritions are
1) Lenovo's System Drive
2) Lenovo Recovery Partition
and 3) "Data" partition I created.

I want a solid working W7 OS back.

What's best way to proceed?
1) Run Rescue and Recovery and do the upgrade again? Seems like a lot of work but at least will be back to factory state.
2) Do a repair installation using the W764 DVD? I understand I would have to get a W764 Ultimate SP1 DVD or uninstall SP1 and use the W764 Ultimate DVD I have.

I want to keep all paritions listed above. Maybe use this as an opportunity to expand the OS parition a little but its not absolutely necessary.

[ElbertR]

Tried running the System File Checker?

"SFC /SCANNOW" in a command prompt window.