I have installed an SSD disk and for some reason when I click on it the file explorer hangs. On the other hand there is no problem using that disk with a console or with Total Commander. The disk works: I have copied a game on it with TC and run it.
I am running Win7 64 with another SSD as a disk cache (intel smart response)
Solved! The intel drivers must have been confused because the second disk was also used as a cache at one point earlier and it still had a partition configured for that (invisible in the disk manager but visible in the intel RST tool). After repartitioning problems are gone.