Well, not always completely stupid, but sometimes quite surprising in terms of how much people don't think or research before buying their equipment, or think or read or experiment afterwards. For any and every stupid question here, there's a snappy (and equally stupid, though true) answer, generally followed by a little actual non-sarcastic insight...
-- Dragon

1. How can I plug my (mixer, toaster, hamster) into my (sound card, 4-track) when the cables are different and especially the plugs on the end?

Use cables whose ends match.

If you can't find any of those, buy adapters. Try Radio Shack or a good music store.

2. Oh. Well, how can I convert (an MP3, a CD, a WAV file) into (a WAV file, RealAudio, a CD, an MP3 file)?

With a program that converts one file format to the other.

There are zillions of free programs around for this sort of thing. Try Nonags.

3. How come all my sound is distorted when I record?

Because your levels are too high.

If your actual signal levels match (see this page for a discussion about mic and line levels), then set your main recording faders or knobs to about 70% of maximum. Now the level meter for the channel you're recording on should average around 0 dB (with peaks to no more than 6 dB) for recording on analog media (that's tape, bunky), or peaks to no more than -1 dB for recording on digital (you don't ever want to go over 0 dB on digital, and it can be boosted later in software).

4. Which (sound card, mixer, multitrack, computer, microphone) should I buy?

Whichever one you want.

See this page for why I don't usually answer that question when asked that way. But if you take the time to research the different products in the area you're looking at, read and understand the specs and features and what they imply, and figure out which ones are most important to you...you will not only know what you're doing but will have answered your own question!

5. What's a sound card?

Oy vey...

6. OK, you told us how to record from tape to my computer to eventually put it on CD, but I want to copy my old vinyl records to CD. How do I do that?

Push the $#@&*! record button.

What makes you think that recording one sound source is any different than recording any other sound source? Plug your dang stereo receiver's line outs into your sound card's line in, and do it!

7. I'm still confused about all this CD recording stuff. I just bought a new CD recorder and installed it in my computer. How do I make audio CDs?

Read the effing instructions.

Every single CD recorder sold for computer use (except relatively rare OEM-only bare drives) comes with a program specifically designed to let you make audio CDs. Find it, install it, and use it.

8. I was interested in buying a guitar but needed to know the difference between a Strat guitar and a bass guitar.

A Strat has 6 strings and a bass has just 4, so clearly the Strat is a better deal because you'll get more for your money.

I strongly suggest you learn something about guitars and playing guitars before you waste lots of money.

Try The Ultimate Guide to Buying Guitars

But really...don't just run out and just BUY something without learning to play first. What if you buy a guitar with a thin neck and find out you need one with a fat neck?