I am experiencing the same problem or something very similar:

the ENB-GUI shows up, the mouse-cursor remains a hourglass and it's stuck in it's starting position.

Already tried:
- Closing all the potentially interfering processes (Fraps, for example). [result: still stuck hourglass]
- Launching Skyrim with the original exe from ModOrganizer instead of SKSE_launcher. [result: still stuck hourglass]
- Launching Skyrim from the regular Steam launcher instead of ModOrganizer. (therefore no mods). [result: still stuck hourglass]
- Uninstalling SKSE at all and then repeat the previous tests. [result: still stuck hourglass]
- Launching Skyrim with compatibily options and admin rights. [result: still stuck hourglass]
- Removed any ENB-related files with the intent to check the behavior of the Skyrim-console mouse [result: the Skyrim-console mouse behaves regularly].

Note: I am using Windows 8.1 preview. Could that be the problem?

I've exactly this problem only with Win8.1

I can't do anything, don't have win8 and will never buy it.