I solved the problem!
In the event viewer I found 2 errors regarding the IAStorDataMgrSvc. The first one stated:
IAStorUtil.StorageAction.VolumeCreate action failed: FailedToClaimDisks
Feeding google with it results in only 2 hits (now it might be three ). The first one helped me out. It was the antivirus software ESET, which caused the trouble. Only deactivating it wouldn't help. I really had to remove it temporarely. Now it works!
I had the same problem and temporarily removing eSet, rebooting, installing Intel's SRT via the RST program (success!), then reinstalling eSet (be sure to keep your Username and Password for eSet...it calls for same on reinstallation)
Thanks to ander1969 for posting the solution!