OK i fixed it with the following
When i booted ubuntu to get teh hardware specs i saw on the very first thing, that it asks me for my WLAN PASSPHRASE to enter, which appaerently kept MINT from booting X properly! (BUG ATTENTION)
So i manually switched the WLAN off (HARDWARE TRIGGER)
Now i can actually see the complete MINT Desktop experience!
I pres install now!