I'm sorry to keep bothering (or whoever answers) but I don't completely understand. I'm going to leave the new install alone, except to stick some files into a folder (don't replace them, just leave the old files alone?) The folder in the new install, is it
Computer>Local Disk>Program Files>Bitcoin
Thats just where the .exe File is, because windows is like that.
The blockchain, the wallet, everything but the .exe file is in -well and some other "tiny" files- %APPDATA%\Bitcoin.
Just hit WIN + R and type %APPDATA%\Bitcoin hit enter and you are there.
The folder in "programm files" should be ~30 MB in size
The one in appdata ~20 GB
Putting the 20 Gigs of data and your wallet in the wrong folder will do nothing but fill your harddrive.
If all this gets to complicated just
- start the new install and let it sync
- close bitcoin core
- go to %APPDATA%\Bitcoin
- if there is a wallet.dat rename it to wallet.dat.backup (just in case)
- copy your "old" wallet.dat there
- start bitcoin core