No sound?

I can't find anything relevant to my question anywhere without people saying how they have no sound after an upgrade from XP. Mine is NOT an upgrade and has only has Vista on it as far as I know.
About 2 months ago, I bought an Acer Aspire 5100 with Vista from Circuit City. Everything has been working well and no problems up until Thursday.
My sound stopped working in Ruckus, iTunes, Windows Media Player and Center. However, it worked online such as YouTube and whatever. I tried everything (that I could do without messing up the computer) and nothing worked. I tried updating the RealTek Audio/Sound driver, but that didn't work. I then uninstalled and downloaded the driver from the RealTek website. It worked fine. Now, a few days later, the sound has stopped completely. Nothing online, nothing in media players. I have uninstalled the driver and reinstalled it countless times, but nothing is working.
It seems to me that I can't get any computers to ever work well enough. There's always a problem. I had a IBM T23 (my first laptop ever; was great until it was getting slow). I then got a T30 (my mom bought both the T23 and 30. Her choices) and that was horrid. Hard drive got fried and then had another one put in and then the battery leaked acid into it and here I am with computer number 3. Both Ts were used and at least 3-4 years old when I got them. The Acer was brand new, never used.

Any ideas as to how I can solve this once and for all?

Hi! You can bring it to Circuit City and have it repaired or replaced. That's what I do if it's still under warranty. You might end up voiding your warranty.

Did you try uninstalling the soundcard too? Go into your hardware manager and uninstall it after uninstalling the driver, then reboot and re-install. If that doesn't work, try restoring to an earlier system restore point. And finally I'd try a repair install of Vista.

http://www.newegg.com/Product/Produc...82E16829120102 something like a new soundcard with vista support might solve the problem? I ordered a replacement for mine when I started having driver issues.