login problem

Check the network adapter / driver may be outdated; I found with some Intel Pro network drivers were updated, which increased login times.

Check also preferred wireless networks if it's a wireless machine; these automated profiles can slow down a machine when there are too many.

Troubleshoot the login without any wire/wireless connection, login as admin monitor the speed.

If these don't apply, you may have an OS issue; re-image/reinstall OS would be my next suspect in this slow login performance.