microphone working once, then not at all

Hi, I installed Xubuntu 12.04 a while ago (CAE version of linux). I can't use updates without losing access to terminal. So, I'm kind of stuck with this version if I want all the nifty add-ins and such. My computer is an HP G70 laptop (HP G70 463CL).

So, I was hoping to record audio with my microphone for a video. Normal sound output has never given me a problem (output through speakers or headphones).

Microphone (inteal and line-in both not working), on the other hand, is kind of not working, at all so far as I can tell. I've tried the following fixes recommended on forums:

1. Install/run alsamixer, edit lines in alsa-base.conf, using "sudo medit /etc/modprobe.d/alsa-base.conf" minus the quotes of course. Attempts include:
alias snd-card-0 snd-hda-intel
options snd-hda-intel model=auto
options snd-hda-intel position_fix=1 enable=yes
I have tried various options for the "model=" field, including auto, hp, dv5, and a few others.
2. I've tried installing and reinstalling pulseaudio and pavucontrol various ways, with no results that have worked.
3. I've tried unmuting (default is unmuted for me), changing sampling rate from 44100 to 96000 Hz (which is what the hardware on my system seems to default to, while the software defaults to 44100 Hz even after I have changed/updated it to 96000 Hz). Of course I've also tried unlinking the chaels, lowering the volume in one chael, still nothing.

I had it working one night before I went to sleep, and when I came back the next day to record my video, no sound. I can't remember what I changed right before it started working, but it was no longer working when I came back the next day. Basically, when I pull it up in pulseaudio for a test, it shows a low level of noise, then stops trying to receive input altogether (audio input bar freezes up). I've recorded it from terminal using arecord, and it's a low buzzing noise. I've tried tapping the microphone or speaking really close into it, with the input volume up, but it doesn't respond to anything, just a low buzzing noise.

Any suggestions? I noticed on this forum a suggestion for what troubleshooting steps to take before posting, but I'm not sure how up to date it was, and it said something about 3 hours of work just to get things working correctly. Like most reasonable people, I don't want to waste another 3+ hours just to find out it still won't work at the end. Plus, my sound itself is working, just the microphone is having issues. Again, not excited about a 3 hour tutorial/instruction for troubleshooting, but I might try it out. If that fails, I think I'll say goodbye to Ubuntu, and trade it back for Windows Vista. If that doesn't motivate people to help me, I don't know what will. (Truth is, I'll probably just find another version of Ubuntu that works with my hardware and just manually install the software I use, but just pretend I'm going to reinstall Vista or some other OS that linux users hate, so you feel the need to find a solution).