Re: Sound Drivers
Looks like from your device manager image you have a second high def sound device which has not been installed properly, perhaps missing proper drivers. This may be a product of your video card having high def capabilities, so double check and make sure you address that issue by either updating and installing the proper drivers for the device, uninstalling (removing it from the system if add on sound card) the device or disabling the device to insure that it is not in some manner contributing to your current issue.
Additionally, right click the "Windows Speaker" (not the Realtek Speaker) in the notification area (bottom right near clock) and choose Playback devices and confirm that you have the correct device selected as the default playback device and make sure that your speakers are configured properly and that you have selected properly from the options (Stereo, 5.1 Surround, etc.,) in respect to what you are actually using.
Yesterday was, Today is, but ahh Tomorrow...mystery, suspense and a promise of hope.

Operating System Windows 7 Ultimate 64 bit
Computer Type Home built
OS Service Pack Service Pack 1
Internet Explorer Version IE9
DirectX Version 11
CPU Type and Speed AMD Phenom II X6 1090T Black Edition Thuban 3.2GHz
CPU Cooling Stock Factory Cooler
CPU Idle Temp 32C
Motherboard Chipset GIGABYTE GA-870A-UD3 AM3 AMD 870
System BIOS Revision Award F5a (beta) 11/15/2010
System Memory Type G.SKILL Ripjaws Series 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666)
System Memory Speed 1333 currently underclocked to 1066
System Memory Clocking 7, 7, 7, 20
Video Card Type and Speed Nvidia GeForce GTS 450 1Gig DDR5 DX11
Video Card Cooling stock
Video Card Temperature 32C idle
Power Supply Unit (PSU) Antec EarthWatts EA750 PSU
Computer Monitor Dual Dell ST2320L
Sound Card Integrated RealTek HDA
Speakers Klipsch
Headset/Microphone Altec Lansing
Hard Drive Two Seagate 500 gig SATAII's ST3500418AS ATA
Optical Drives Lite-On DVDRW x2
Keyboard and Mouse Logitech USB Optical
Modem-Router Type Arris MODEL: TM602G / Microsoft MN700
Network Adapter Realtek RTL8102E/RTL8103E Family PCI-E Fast Ethernet NIC
Printer HP InkJet 990cxi
Network Speed WD Passport 500gig USB 3.0 BackupDrive
USB Controller NEC Electronics USB 3.0 Root Hub
Gaming Console Xbox 360
Anti-virus Software Microsoft Security Essentials
Productivity Suite Office Pro Plus 2010
System Install Date 2011-01-25 21:59:23 on this drive
Computer Skill Level Certified Professional
Windows Experience Index 7.2
Favorite Game FarCry (original, 2 sucked)