26gb of spaced lost after upgrade

[therebel292004]

Recently, I upgraded my hdd from 320 to 500gb. I made the mistake of installing aconis which did NOT properly clone the drive, but did create an error with the screensaver starting up. And this error was cloned over to the new drive when cloned with EaseUS Disk Copy. I am now unable to access the original drive cause I tried to find out why I have 10gb less space used then the original drive did.
I tried to repair the screensaver issue (missing msvcr71.dll) by using scannow, chkdsk, virus scans, and a registry cleaner. Found a article for the issue which said to "repair" the OS by upgrading to the SAME version as I have installed. I did so, and it used up an additional 30gb of space on my drive. Does anyone know what would cause this and how I can get that space back? I ran the disk cleaner, and cleaned the system files, but that only cleared out maybe 4gb taking the wasted space down to 26gb.

If it helps, my original drive had Windows 7 Home, and I used the online upgrade to go to Win7 Ult.
The upgrade I did on the new drive I used a Windows 7 Ultimate ISO from digitalriver.

 

[whs]

I would analyse the partition with WinDirStat. https://windirstat.info/

 

[therebel292004]

I know the date of the "repair" but how will this program help me find and remove whatever has been dumped onto my drive?

 

[whs]

First you have to find out what's on the disk and what does possibly not belong there. For that you run this program.

 

[therebel292004]

Ran the program,,, but can't make head or tails of the program. Found another article where someone had the same problem. They ran defrag and it said like 1% fragmented, but defragged it anyways and got their missing 16gb back.
I originally had 232gb free before the "repair". After was down to 202gb free. Ran the defrag and it said 1%, started defrag and after only 3rd pass, 33% consolidated, I am up to 220gb free space.
It would seem there is some sort of bloating effect from the Upgrading process that can be fixed by simply defragmenting the drive.

 

[therebel292004]

Okay, gained back 18gb of my missing 30gb, still about 12gb "missing". Starting to think a CLEAN install is the only fix for this issue. Unless I can restore my old drive to a bootable state.

EDIT: Old drive does NOT seem to be able to restored as boot drive.
Accessed the hidden Administrator account, and ran defrag, got back another 6gb of space. Only 6gb missing now.