Windows 7 Home slow logon due to Group Policy Client?

One of my machines which is running Windows 7 Home 64-bit has recently developed a problem with slow login which appears to be caused by the Group Policy Client. This is what I know so far:
* boot time is normal
* after logging in as any user, the machine sits at the "Welcome" screen for a long time (minutes), and sometimes this is followed by a long interval with just a black screen and the mouse pointer.
* eventually the desktop appears and things run smoothly after that.
* logging in to Safe Mode with networking is fast.
* occasionally, such as after installing a Windows update, one logon may be normal but the next one is slow again.

I have run on-demand scans with MBAM, no issues found.
I have tried the Tweaking.com all-in-one Windows repair tool with no effect.
I have installed the "slow boot slow logon" rollup KB2775511 with no effect.
I have installed the Windows Performance Recorder and obtained a boot trace, but all I can see is that winlogon takes a long time and that group policy also take a long time.
Selective boot using msconfig does not improve things.
Safe mode logon is fast, and Group Policy Client is not running.
I hacked the registry to disable Group Policy Client and that gave me back fast logon but it also disables standard user logins so this is not an option.

At this point I don't know what to do other than trying an in-place upgrade to reinstall Windows 7. Google returns lots of hits about slow logon and group policy but most of those seem to be scenarios where the machine is connected to a domain. This machine is not connected to a domain so I'm not sure why Group Policy has suddenly slowed things down so much.

Thanks for any suggestions,
Peter

 

Thanks for the suggestion. I have autoruns and it did find some entries where the file was not found. I disabled those but still have slow logon. I have Process Monitor and Process Explorer as well but I'm not sure what to look for when it comes to Group Policy...

 

My reasons for suspecting Group Policy are largely based on the observation that logging in using Safe Mode is consistently fast, and that when I disabled the Group Policy Client service in the registry my normal Windows login was also fast again. I'm also pretty sure there was something in the performance trace but I would have to look at it again - it is a very useful tool but like process monitor it produces a lot of data and it is still difficult to tell why something is taking longer than expected.

I also don't see any performance problems once the desktop is available.

I have tried uninstalling various applications that were installed or update recently (e.g. MBAE, Microsoft OneNote) but none of that has any effect. Disabling all startup items in msconfig also does not help. Disabling WiFi and plugging in to a wired network connection to my router does not help.

The other thing is that this appears to affect the first Windows logon after a reboot. If I reboot the machine and go away for a few minutes before logging in, the login delay does not occur, and if I log out and log back in that login is also fast. But when I reboot and immediately try to log in is the time I get the delay.

The affected machine is a Dell Vostro with a quad-core i7, 6 GB RAM and a WD Black^2 dual-drive. That was a recent addition but the problem also occurred when I swapped the original Seagate 7200 RPM HDD back in so I'm pretty sure it is not an issue with the Black^2.

 

Yes it did. I went ahead and did a repair reinstall/in-place upgrade and reapplied the patches (thanks Autopatcher). So far things seem to be back to normal so I'll chalk this one up as a practice run for a potential upgrade to Windows 10 later...