Well, my computer crashed when I was watching a video on Giant Bomb. Don't know why, it just did. Restarted it, and all of a sudden, everything sounds really tinny. Have any idea what I can do to fix this?

Well, what do you know, that actually did the trick! Windows had some updates to install, and before you know it, sound is pumping through my speakers in pristine quality. Thanks!
EDIT: Whoops, no, spoke too soon. Still sounds really bad.

That's what I'm working on right now...
EDIT: No dice. I reinstalled the drivers Vista came with, and I'm still getting very poor audio quality. I'm plugging in my headphones to determine if the speakers aren't actually malfunctioning...
...
Well, it sounds better on my headphones, but I am unsure if that's because headphones are different in location, size, and quality than speakers (though my headphones are pretty high in the quality department). Should I just wipe the memory clean and do a fresh install?

Well it'd be worth trying the speakers in something else. Uninstalling the drivers, pulling the card, rebooting so it picks up the change and then reinstaling the card might be a good next step.
Assuming its not a laptop that is
Using a restore point might also be worth trying, its kind of what they're for after all

Well, I completely wiped the hard disk and reinstalled Windows 7. Sound still sucks. I'll probably steal one my siblings' speakers when I'm at a sane hour, so I can see if it is the damn speakers...

Hmm, I had a similar problem the other day, but that must have been a sound card issue. I was listening to some music on YouTube, when playback suddenly switched to mono for no discernible reason. It wasn't the video I was watching, I checked, because it switched mid-video, and when I went back to the beginning of it, it was still in mono. All other videos were too.
I just closed the tab with youtube and started up an MP3 in Media Player, that fixed it.

Yours sounds more like the program stopped accessing the sound hardware properly whereas cheese's sounds more systemic (or possibly dodgy speakers)

I've had these speakers for 5+ years. I opted out of getting a new screen and speakers when I got my computer in 2007. Do you think that's enough time for them to need replacement? They're Dell speakers.

The smallest of things can break speakers. Frankly I doubt it would be physical hardware but the best way to test is to plug them into an mp3 player or something and see how the output sounds

I just tested it with my iPod Touch, and yep, seems to be the speakers. Damn. Well, they had a good, long run. Just can't believe a crash caused it to happen.

Was it accompanied by a screechy noise of some sort? Might have torn the fabric

I don't think so. You can't even get to the fabric with my speakers, so I can't really look unless I smash it apart or something.
Looks like I'll have to go shopping for a new pair. Maybe Best Buy has some inexpensive speakers...

So you reinstalled windows for nothing and it turned out that my first real suggestion was right all along...