Windows 7 Pro Long Shutdown Can't Find Issue?

For the last 2 days i have been trying to diagnose why my PC is taking anything between 1min 30sec and 3min to shutdown.I found that if i booted into my desktop (fully loaded) then shut down, my shutdown time is between 9 and 12 seconds! However if i boot into desktop then use any program or game, then i had the long shutdown time.Event log showed the ShutdownKernelTime to be between 120000 and 150000 when i had the long shutdowns.For your info, for testing purposes the programs i used are firefox 10.0 (opening 3 websites) and Windows Live Mail. IF for any reason i got a successful quick shutdown after running these i then ran GTA IV for 5min then tried a shutdown.So far i have tried: Disabling all services and startup entries in msconfig. Got same results as above Various combinations of service and startup entries in msconfig. Same result as above Booting into safe mode running same test. I get a successful quick shutdown. Checked the registry for any page file clearing at shutdown. Complete disk defrag Advanced System Care 5 Scan and repair Updating any drivers if update available Running a shutdown trace using Windows SDK. This however works by restarting the PC then running the trace so imitates me booting in to desktop and shutdown again which works fine so as expected the trace shows everything working as it should. I tried adding firefox and Windows live mail to startup folder hoping just the simple opening of these programs would cause whatever happens to give me a long shutdown time. It seems though like i need to open the 3 websites to create the issue however the only time to do this would be the delayed shutdown stage which im advised you shouldn't touch anything at this stage? could anyone advise on this? Hopefully one of you's out there with a bit more knowledge can point me in a new direction that puts me closer to solving this.I used to have Ntune (Nvidia) for GPU Fan control and MSI Afterburner for GPU Overlocking, however after trying one after the other enabled/disabled etc i found i got successful quick shutdowns but long shutdown then returned after playing GTA IV. I uninstalled MSI Afterburner and now only use Ntune for both GPU Overcloking and Fan Control. Current Startup's enabled:Realtek HD Audio Manager RocketDock NVIDIA Ntune Avast Antivirus Quote Originally Posted by whs In regedit,navigate to HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControl Double click on WaitToKillServiceTimeout and set it to 2000 - that is milliseconds. Then OK. Initially solved the long shutdown if i used my programs as detailed above but has since returned after using the programs for a longer time and watching a HD game review.