Contact Cooler Master for a replacement front audio cable or buy a generic one from an electronics store. If you feel inclined you could also make one.
A front audio panel cable looks like this
http://www.logicsupply.com/images/photos/cables/FrontAudio_big.jpg
Whenyou get the replacement encure that the pin block on the end is HDA and not AC97 and plug it into the motherboards Front Audio connector- it is a 9 port block like the one shown here
http://www.fixya.com/uploads/Images/3C3CD07.jpg . The top row of ports (with the missing pin) are numbered 2, 4, 6, 8 (empty), 10. The lower rank are 1, 3, 5, 7, 9.
If the cable you get has individual or double pin sockets (rather than a 9 pin socket) you'll see that the sockets are labelled. Common labels are:
MIC VLL or MIC BIAS this connects to port 3
MIC IN this connects to port 1
EAR (or Spkr) L connects to port 9
EAR (or Spkr) R connects to port 5
GND (or Ground) connects to ports 2 and 7
+5VA or VCC connects to port 4
Line Out R connects to port 6
Line Out L connects to port 10
If you want to keep your existing motherboard then you can disable the onboard audio in the motherboards BIOS. Uninstall the driver - Should be Realtek as most DFI boards use the ALC885 codec either as onboard or as a Bernstein add-in card. Add your new PCI or PCIe soundcard and install it's drivers.
If you are planning on getting the Gigabyte board anyway then the Razer will work fine.
As mailpup indicated, your graphics card will work on the motherboard. If you plan on getting the Gigabyte mobo then change "Init Display first" from PCI to PEG (this is under the "Advanced Bios Features" tab on the main menu page.