High start up CPU usage only goes away after sleep mode

[ro2207]

Please help me out! After entering windows, my cpu usage never drops below 100%
Most CPU intensive processes I can observe in task manager:
Starting with taskmgr.exe (60-80%)
Then WGAtray.exe takes over (50-80%)
And finally wmiaprvse.exe pushes the system up to 90%, with the WGAtray process also showing up every once in a while (not allowing me to use the computer at all).
The weird thing is that if I press the sleep button and then wake up the pc, performance is back and CPU usage settles all the way down to 5%

I've tried cleaning the registry and running mcaffee with no success.

Does anyone know what could be causing this erratic behavior?

Thanks

 

[ro2207]

It seems my problem is due to a driver conflict with my sound card's hdmi audio output. As soon as I disable "UAA high Definition Audio" driver in device manager my cpu usage drops down to 5%.
I'm now trying to find a solution to prevent this driver from being enabled on start up (even if you disable it on device manager it automatically gets re-enabled on start up). So I installed DevCon, IDed my driver and created a .bat file in the start up menu so it gets disabled upon start up. It is not working. It seems DevCon tries to disable it before it gets re-enabled by windows on start up. If I manually run the CMD, it gets disabled. I want to somehow block this driver! It's driving me nuts. Tried uninstalling it, but windows automatically reinstalls it. I don't understand why devcon is not working. Any help will be greatly appreciated.