Yes, you can, if you have an amplifier. Connect the speakers to the amplifier and the amp to the line-out of your PC's sound card.
You can use standalone amplifiers or even built-in amplifiers from different sound systems. Just make sure you have an input and an output you can use.
yes you can I bought computer speakers from logitech and they came with an adapter so i could use them on my tv
yes anonymous@oola.com
If the motherboard has a mic jack,if not you need a sound card with one. It will only be as loud as the software allows, it is not an amplifier. But you can run it to an amp or your stereo and then to speakers.
as i understand you question u want to record audio in you computer without mic. you can use stereo mix option
yes, they are plugged into outlets
yes , you can use a turntable on my computer as well as my stereo system anonymous@oola.com
Yes - you can use them. But you will not get the sound quality that you will out of matched speakers. Also, you could blow the speakers if you try to "crank it up".
In most cases; yes. That depends on the humidity of where the car is going to operate. If the environmental conditions are harsh, the speaker membranes must cope with it. Stereo-speakers, generally manufactured for indoor use might not. <><><>
Magnets.
Yes and yes
Then your radio probably isn't grounded properly.
No. Not all of the computer speakers have to be plugged in. You can just use the 2 front speakers and add rear ones at a later date.