Windows 7: Win7 Enterprise Login Freezing

I work at a company with 80 or so computers running Win7Ent. With increasing frequency over the past month or so, a number of the computers have been hanging on login. Specifically, the user hits ctrl+alt+del, enters their domain creds, but then windows hangs on the 'Welcome' screen for 10-15 minutes (sometimes up to 30) before finally proceeding with the login. Afterwards a check of the event log shows one or two services (but almost never the same services) had timed out during the boot.

I did the usual Google routine, but all I could find was reports of the background bug which should only cause a 20-second delay.

Does anyone have any advice?

I've had a similar issue with XP. Now I'm no programmer, but from what I understood (for me) it went like this: the Windows WLan configuration service timed out for whatever reason (maybe the router didn't respond, or whatever). Windows would still boot, but it would take ages, 5 minutes, 10 minutes, etc.
What I did back then is write a little script that deactivates the service and another one to reactivate it, so that I could deactivate it when shutting down and reactivate it when starting up - that solved it.
I've had multiple services timing out as well, however, it was only the fault of 1 specific service that hindered the other service's proper execution.

If you know which services are causing the problem, maybe you could do something similar? Integrate the script in a way that it automatically executes when a user shuts down and disables the service and then when windows has booted it re-enables the service.

I've thought about doing that, but it seems like there's no specific list of services that are the culprits. I can't very well disable EVERYTHING.

For further information, I've found that the only reliable (if temporary) correction is to perform a system restore. Affected computers seem to boot properly after restored back one or two days.

It turns out that it was Forefront that was messing up its indexing of excluded network folders. Microsoft is apparently working on it. 'Cause... you know... antiviruses should clearly bring a 21st century operating system to its knees, especially when the antivirus and OS were made by the same company. *sigh*