No sound just static after Windows 7 clean install

I recently upgraded my PC from Windows Vista HP 32 bit to Windows 7 Ultimate 64-bit (build 7600). I have not been able to get any sound except static and popping from my speakers. I have tried updating my drivers to the most recent Realtek drivers from their website but still only static. Acer does not offer drivers for Windows 7 for my model so I also tried running their Vista X64 audio driver in compatibility mode to no avail. Also, each time I try to restart, my computer takes about 15 minutes to boot. It gets stuck at the starting Windows screen for the majority of that time and it looks like the hard drive does not show any action. After about 15 minutes it eventually boots up. Any help would be greatly appreciated. My system specs are as follows:

System Manufacturer/Model Number Acer Aspire M5100
OS Windows 7 Ultimate 64-bit 7600
CPU AMD Athlon 64 X2 4400
Memory 4GB
Graphics Card(s) ATI Radeon X1200 Series
Sound Card Integrated Realtek ALC888-GR, colayered with ALC883 Realtek

Thanks Daryl, I have downloaded Acer's driver, since they don't offer a Windows 7 version, I downloaded the Windows Vista 64 driver and installed it in compatibility mode. Unfortunately I still only got static. I have also tried removing all audio devices via device manager before installing the drivers. Is there anything else I should try?

I don't think I have forced an update, how can I do that?

I am doing a forced update now but it appears that the only thing updating is files for MS Office. Also, I restarted my computer and now there is a red X over my volume icon in the taskbar and when I mouse over it, it says no audio output device is installed. My Realtek HD Audio device is no longer showing in device manager either.

Hi, Go into Device manager and click on Action, and Scan for hardware Changes.

Did that, it did not recognize any new hardware

Hi just reread your first post, try this first.

Scannow.https://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html