I record music on my computer by plugging my guitar through an extension then to the mic input, well i did do this until a couple of months ago,my sound went out and my mic. After a couple of days the sound came back, but my Mic doesnt work, it wont record anything.

Any help?

first thing is first i guess i would have to ask what you were doing when you noticed this problem. It might be as simple as reseating your sound card...or it might be that you need to reinstall your sound drivers. In addition, try a virus scan...anything is possible these days. you could try reseating the sound card because if it is loose then your card will work intermittently. In addition, for whatever reason you could have a problem with your sound driver. Oh and if you have on board sound, don't worry about the loose card. If you do have on board sound the first thing i would suggest is to check and update your multimedia sound drivers, and check to make srue the Mic volume is turned up. Hope that helps a bit, reply back if you have any more questions or updates. Good luck from a from a fellow guitarist. :)

I had my guitar pluged into it and it made a noise.....how do i update my sound cards?? Or better yet where do I update them? Or how do I reseat it?

What noise did it make?? Was it through you're speakers or did it sound like it came from your CPU? To update ANY driver you would simply right click your My computer icon, and the click properties. It should then pop-up a system properties box. Then click the hardware tab, and the click the device manager button. You should then see a list of hardware. You'll want to find the plus box that says "sound, video and game controllers". In this selection you should see a list of your sound and other multimedia drivers such as codecs yadda yadda. You will want to find the Audio device that the computer uses. It will say something like C-Media Audio device. You can right click this and simply click update or select properties to view other properties of this driver. You might want to do this as well because it will tell you if your device is working properly. In addition, reseating the card is simple. You open up your box and find the sound device. It will have the 11mm headphone/mic/Aux jacks on it. You just unscrew it from the board, pull it up, and get any dust from it that might have settled on it. After this just set it back in there and screw it down. If you don't see it in one of your motherboard slots, then you have an on-board sound device, and don't worry about reseating the card.

Like A Cracklily noise from my speakers im pretty sure, but my sound came back so I would think my mic did too

Sounds like it might be a loose jack, try wiggling it and seeing if that works. Be gentle though, because if it is loose it's going to be fragile.

Ok Here is another explanation of what is happening...when im at my volume control properties and im listening to music, if i turn the mic volume all the way up, my speakers make a crackily noise and it cuts out the main volume

Did you try wiggling it?
Maybe reseating the card might help, but it sounds like a bad connection because when you raise the volume on the mic, it's changing electrical properties on the card, which makes that crackling noise. So it's trying to work but it can't get the connection.
How old is the card?

As old as the PC which would be 1999ish

Alright. you might need a new sound card. nothing amazing just something newer the '99. It deffinately sounds like the card you are currently using is having some connection problems. I would try reseating the card, and if that doesn't work you might try buying a new one. Maybe a used one off from eBay.

Alright thanks man!

Alright, I reseated it and nothing happened any other suggestions?