I just upgraded my computer from xp to windows 7 home premium and have no sound. When you look in the device manager it says the sound is working fine but it isn't. I have a Gigabyte GA-81945PLGE Motherboard and 6 channel AC97 Audio. When you try and play anything it shows that it is playing but is very silent. 
My Computer
- Computer type
- Laptop
- Computer Manufacturer/Model Number
- TOSHIBA SATELLITE L500 PSLS9A=01U012
- OS
- WINDOWS 7 HOME PREMIUM 32 bit
- CPU
- INTEL (R) CORE (TM) i3 CPU M 330 @ 2.13GHz
- Motherboard
- TOSHIBA NSWAA VERSION 1.00
- Memory
- 4.00 GB SODIMM
- Graphics Card(s)
- ATI MOBILITY RADEON HD 4500 SERIES (MICROSOFT)
- Sound Card
- MICROSOFT HIGH DEFINITION DEVICE
- Monitor(s) Displays
- GENERIC PnP MONITOR
- Screen Resolution
- 1366 X 768 @ X 32 BITS (4294967296 COLORS) @ 59 Hz
- Hard Drives
- WDC WD5000BPKX-2HPJT0 ATA DEVICE 465.76 GB
- Mouse
- LOGITECH
- Internet Speed
- NO INTERNET
- Antivirus
- NOT INSTALLED YET
- Browser
- INTERNET EXPLORER WHEN INSTALLED