Windows 7 Mute problems

I have an HP 8510W laptop.

I am running the Windows 7 X64 7057 Build.

My problem is this:

Windows seems to be turning on the hardware mute on my laptop after a certain (or perhaps random) amount of time after a sound is played. When the OS does play a sound, it seems to take between 5 to 15 seconds for the OS to un-mute my laptop and play the sound.

This is annoying when I am playing back movies with software such as media player classic as sometimes I pause the movie and come back a minute later, with the laptop on mute (hardware mute as depicted by the mute button on my touch sensitive keys above the keyboard) and try to resume the video. The video starts playing without sound and then a little later, the video freezes and the sound starts playing. The video remains frozen whilst the sound catches up to the correct place before letting the video resume.

I am mainly talking about the hardware being muted as the windows volume icon speaker does not show it as muted and if I open it, the mute is not on. I can force the mute on and off to correct the problem and when I do this, the volume control window freezes for a bit while it thinks and eventually comes right.

I'm not sure if this is a driver issue with my specific laptop but I'm really unsure as to how to go about solving this issue.

I understand that this is a BETA operating system and I'm not expecting magical hotfixes... but I don't have any 'send feedback' button anymore so I thought I'd better send it in somehow. Also, this is where Windows 7 sent me to 'ask' this question, so don't tell me it's in the wrong place as I'm well aware it's posting it into the vista section.

I didn't experience this problem on build 7000 though, so this seems specific to the build.

I tried updating to the latest driver I could find, which is: http://www.drivercure.com/driver/driver_vendor.php?id=54A5DDEC-9AA6-4C19-A85E-C6BF73228E1D

Didn't seem to help.