I recently upgraded the hard drive in my desktop.  I used a cloning software (that came with the drive), so I wouldn't have to re-install the OS and applications.  Ever since, I've been prompted to activate Windows.  I click on activate online, and get the following message "Windows can't activate. Try again later.".  I've read multiple posts that say this is a firewall setting to running repair options, none have worked.  I tried Slui.exe 4, so I could call in and re-activate, and that hangs and never gives a confirmation ID.

Any ideas? I'm about ready to give up and just re-install.  I was about to purchase a new activation code, but found out that won't work since this is an OEM version, and I'd have to re-image anyways.

I would suggest you to reinstall the OS, since you're not able to generate the confirmation ID. 

Hope you have checked this : http://www.urtech.ca/2012/08/solved-windows-cant-be-activated-right-now-windows-8/

Hi,

I agree with arnavsharma. 

Since it is OEM system, the activation information is highly related to Hardware information, to reinstall the system with the recovery media can be the better way with activation successfully.

Or you can buy the retail version and perform the clean installation.