How can i record with my microphone through the recording jack on my Compaq PC?

I'm having a problem recording audio with my microphone. I know my microphone works (tested on different computer) but my computer refuses to record any audio. When I try to adjust the volume for my microphone in the "Recording Control" window, (from double clicking on the silver speaker in the system trey and clicking options -> properties and dotting recording) all the volume sliders are grayed out except the master recording volume. My mic volume is not muted. I have installed latest realtek drivers. When looking in Realtek's Audio Manager and under the mixer tab, the recording sliders are not editable there either. Searching google for other solutions have hinted that the rear pink input in the playback section must be un-muted and turned all the way up. I did this but still have no recording at all. I have also looked for any bios fixes and it doesn't look like gigabyte has any updates for their onboard audio recording. I have also bought and installed a cheap sound card (i Dot Connect 4 channel pci sound card) to see if the microphone would work with that. Unfortunately, the same problem persists. I even disabled onboard audio from the bios to see if just the sounds card alone would do the trick but with no avail. (Also, The card's audio output is working fine.) I now have my realtek audio drivers reinstalled with onboard audio re-enabled. Everything seems to be working fine except I can't record a thing. Any ideas?