So I bought a new headset for about 40 bucks down at Radio shack. My old one [censored] the proverbial bed and I figured i would go with one slightly higher end than my previous one. It worked fine for a while until one day i plugged it into my laptop (usually im using it on a desktop) and i couldn't get the sound to go any higher. I adjusted all the mixers changed all the settings and i could only get the volume to be slightly audible. I figured, oh well i don't use this laptop often anyways.However when i got home and plugged it into my desktop the same situation occurred, again i adjusted all the mixers, changed the settings ,checked the drivers and it still was only slightly audible. So i plugged in my monitors built in speakers hoping it wasnt a computer issue and the speakers worked fine. Later that week i was using the laptop again with the same headset and the headsets volume went right back to normal, i was able to adjust the volume higher and lower and all was right. Brought them back to my desktop and they worked fine there too. Then i was playing Oblivion and the sound of an Oblivion gate was bothering me so i used the volume control on my headset to turn it down a notch. However now its back at that inaudible volume, same as before. Help!
My guess is this: You bought cheap headphones and they svck.

But, for the sake of figuring out the problem:
1. What brand of headphones are they?
2. USB? 3.5mm? 6.35mm?
The problem is likely with your volume control on the headset. Not that that will do you much good, unfortunately.