After a clean install, Win 7 searches for updates forever.
Download this fix: https://support.microsoft.com/en-us/kb/3102810
Disable network(just pull the cord) and reboot, else windows update will be stuck in its loop and block the install
Install the fix you downloaded and enable your network again
After this it should just take normal time(few minutes to half an hour depending on system) for windows update to finish searching.