Hi flester It's not advisable to do either of those two connections even if it was possible for many reasons. Pop over to the recording forum and have a read of the many posts which cover recording to a computer.. The help you need will be there.. ark
I believe you need some sort of interface. I bought a digitech rp pedal that came with cubase LE. The pedal has a usb out to record on computer. You could just put your computer mic in front of your amp or sound hole, and record with windows sound recorder. It wouldn't be the highest quality but it would work.
You can plug a guitar with active pick ups in and get some sort of song. PC style mics will also work. You will find you need an interface device to have better control of your sound but to answer your questions "yes you can" and plug into your mic connection. Use your sound prpoerties in "control panel" to tweak the sound (too hot, too soft, etc.)
I used to be disgusted; now I try to be amused. Elvis Costello