Thanx men!
I got the CLI-wallet working & synchronized, watching the instructions video and some reading around on Discord made the difference.
For those ones who still need to solve it, continue reading. The next might help, first kick back and relax while watching the instructions video https://youtu.be/pMUUs-K-zj0


What I did:
1) Made a .bat file for nxboostd.exe with the next couple of commands in it; 'nxboostd.exe --add-exclusive-node 89.40.4.42
nxboostd.exe --add-exclusive-node 213.80.163.129
pause'
2) Run it, it should start syncing.
3) After that I made another .bat file, this ones for the nxboost-wallet-cli.exe ; 'nxboost-wallet-cli.exe --generate-from-key NEW
pause'
4) Run it. Now ur able to restore ur wallet by ur private keys.

Note: Before starting I deleted the entire old directory where the old wallet files where kept.
Used CCleaner to get rid of the remaining registry key's and rebooted my PC. Once rebooted I installed the CLI-wallet as explained before  


Cheers, keep on mining!