always difficult to remote diagnosis
let's try: unplug ur wacom, remove the driver, check your hard-drive for any occurrence of wacom files (espec. win\system32). check if you have KB3004394 installed, if yes then remove it.
clean registry again (wise registry cleaner did a good job in my case). stop and disable tablet input service in services.
disable antivirus, reboot and install wacom driver again (you took the latest driver and NOT the one from the cd, do you? ). Reboot again and now plugin the tablet -> if it works you are lucky.
If not clean your system again (unplug wacom, remove driver and driver remains), create a new user and try again in the new account.
another thought: maybe some remains of your genius driver, try also other usb ports, check for hidden driver or old genius services.
if nothing works, look into wacom driver setup log for some errors, check windows log for problems.