Ok, so I have a decent computer, an MXL 990 condenser mic, several guitars and various cables. I want to start recording vocals, guitar, violin and piano (eventually) but the more I learn about recording the less I know. My mic doesn't work on my pc but works on the laptop; an issue I have put down to hardware as the PC is custom built. I am assuming that a decent sound card or audio interface will fix this but I don't know whether I need one or the other, or both. I also don't know whether to record using audio jacks, or get a card with MIDI inputs (I am currently using XLR). I also don't know what techniques I can use to get the best quality recordings. I'm at a complete loss.