Changing Audio Devices

Hey all. Every time I restart my PC I get a different list of available audio devices. Or they at least appear different to me and I must admit I'm not a whiz on any of this.

I'm trying to use a microphone headset for use in Ventrilo. I had previously plugged in through a USB adapter but that causes a ringing sound to be heard when I speak. I don't attribute this to Windows 7 or anything like that. I unplugged the USB device and plugged the two jacks into the available green and pink ports on my motherboard. After some tweaking of which input/output device to use I was able to get sound going out clearly with no problems.

The next day when I started my PC, different audio devices were available for selection. Instead of Microphone - 34 High Definition Audio Device, it'd be listed as Microphone - 33 High Defintion Audio Device and things like that. I can hear sound without issue but now I can't be heard at all when speaking. I tried numerous things to no avail last night. This morning when I turned on the PC, the device listed was Microphone - 15 High Definition Audio Device. There's always two listed. One for the front panel and one for the rear. Although the night I got it to work, there was two listed for the rear panel.

Why do these change every day and what might be the reason I'm unable to send out sound? Is it simply the port on the motherboard? Any help would be greatly appreciated. Thank you.

I set the rear jack that is listed as my default every single time and every time I restart the PC it changes the default to the front jack. I don't mind changing it but I don't understand why what is listed changes each time or what affect that has.

I've done that as well. Whenever I go into the devices I enable and set as default the one associated with the rear jack. After that I disable the device listed for the front jack.