That’s really the whole question. I am on Windows 7, 64-bit. I am having this problem with both 3.3 and 3.4. I had previously registered as the free version but need to go to Unity Pro for my job, so this is kind of mission critical for me.
Try running Unity as Administrator, it worked for me.
Right click on Unity (icon or startup option) and select “Run as Administrator”.
Try manual activation.
Manual Activation also locks up. Should have mentioned that. The FAQ I was reading says I need to upload an ILR file. I have no idea what that is.
–edit-- Just checked my machine… no .ILR file to be found anywhere…