Sorry to hear you are having so much trouble.
I suggest you first use a program like Piriform's Ccleaner on your pc to try to completely remove WMDC.
Then shut down and reboot and then download and reinstall WMDC.
I then would check Activesync on your device and make sure that there isn't an old partnership or setup on there from a previous setup.
Then I suggest you make sure nothing else is running on your PC that might interfere with syncing like some sort of firewall, virus, or malware software before you connect your device. Then connect it and your pc should recognize it and you should be able to setup the partnership.
If that fails then I would say you might have a hardware failure of some kind like a bad cable, usb port, or a problem with your device.
Activesync may be messed up on your device somehow and I would think your only option there is to flash the shipped rom(if you are running a custom one) and hard reset. Hope that helps! Good Luck!
