mic input volume too low

Everytime I use sound apps like vent and sound recorder my voice is just too low. It's barely audible and I have all the settings at the very highest. My mic was tested on my laptop and it works fine.

is there a way the volume can be boosted? I'm using Windows XP x64 edition with onboard realtek sound chip.

My headphones is the Koss SB40, which I bought after reading the headphones recommendations thread.

Sound properties >> recording properties, make sure the microphone is turned up. Also hunt around in there for something like "mic boost" or the like. Don't really have an XP system here to look for the exact name, but I think it's a check box (it's another slider in Vista). Vent also has its own gain settings.

every setting is turned up (even in vent). When I talk it's still very soft. Is there anything else I can do?