Give you an install procedure like you read at http://forums.cnet.com/5208-7587_102-0.html?forumID=69&threadID=271360&messageID=2699006#2699006
Do not guess your way to a proper OS install.
I have this laptop that works fine otherwise.
This behavior is quite similar to what it would do under XP SP2 and SP3.
Sound is working fine, no issues, and I hibernate the computer. After the resume, the audio is gone. But the device is not X'ed in device manager, and I can see the Volume level jump up and down in the Volume in the notification area.
The audio will not come back until I either 1. restart the computer or 2. uninstall the device in device manager, and let windows re-detect it and install the drivers. The sound is powered by a device called "Microsoft High Definition Audio" (mshdaudio.sys).
I looked at Microsoft's KB929685 (which tells me to get the latest service pack) and KB937077 (which tells me to install a patch - which will not install - "this patch does not apply to your system")
This has happened pretty much from day one. With Vista freshly installed and also with SP1. Under XP (SP2, SP3), the behavior is similar, sound would be erratic after resume from hibernation.
HP Compaq Presario C303NR
Intel Core 1 T1350 (1.86 GHz)
2 GB RAM
Intel GMA 950 video
Broadcom 802.b wireless module (same as Dell 1390)
Windows Vista Basic