I recently built this system.
Motherboard: MSI P67A-G43 (B3) LGA 1155 Intel P67 SATA 6Gb/s USB 3.0 ATX Intel Motherboard
Processor: Intel Core i7-2600 Sandy Bridge 3.4GHz LGA 1155 95W Quad-Core Desktop Processor Intel HD Graphics 2000 BX80623I72600
Memory: G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL7D-8GBXH
Video Card: EVGA SuperClocked 012-P3-1572-AR GeForce GTX 570 (Fermi) 1280MB 320-bit GDDR5
HD 1: OCZ Solid 3 SLD3-25SAT3-120G 2.5" 120GB SATA III MLC
HD 2: Western Digital Caviar Black WD2002FAEX 2TB 7200 RPM SATA 6.0Gb/s 3.5" Internal Hard Drive
Additional NIC: Rosewill RC-400 10/ 100/ 1000Mbps PCI V2.2, 32/64-bit, 33/66MHz Networking LAN Card
DVD: SAMSUNG Black Blu-ray Combo SATA Model SH-B123L LightScribe Support - OEM
Power Supply: OCZ ZT Series 750W Fully-Modular 80PLUS Bronze High Performance Power Supply
Case: Antec One Hundred Black Steel / Plastic ATX Mid Tower Computer Case
I also have an old Creative 4.1 speaker system (been around for about 10 years from system to system)
It worked flawlessly....until.....this morning my daughter was watching NetFlix and she plugged in the headphones. The sound muted the rears (as it is supposed to do) and sound came through the headphones (front jack) as it was supposed to do. She said some popup appeared to which she didn't read and just hit OK (doh!). Now I am unable to get any sound out of the rear speakers when unplugging the headphones. After much playing around, if I un-check "disable front panel jack detection" in the MSI Audio Manager then the sound once again works from the rear, however (as can be expected) it doesn't mute it when the headphone jack is re-plugged in. Strange, thing is that this worked before this morning. It's like it is always detecting the headphones and therefore mutes the rears.