bump because i'm pretty sure that it's a hardware problem at this point. the audio just broke again after a soundcloud file finished playing (but the youtube videos and media player playlists i've been listening to all day haven't caused any problems) so i decided to do some more troubleshooting.
i plugged in the earbuds i use with my ipod and they made a lot of static, regular clicking noises, and occasionally some shrieking sounds but would not play sound from my computer.
i went under speaker properties and hit the test button, and it gave me this error message:

i went under dxdiag to look for what model my realtek chip was (my dad suggested that because i didn't have a dedicated sound card, it may be an issue with the chip on my mobo) and it gave me this error message:

...but the dialogue boxes under the sound tabs don't mention any problems or anything.
this problem is getting super frustrating because i'd hate to have to restart my computer every time the sound breaks, since my computer takes like 6 and a half minutes to boot up to a usable state.
edit: turns out i have a VIA chip but this discovery doesn't help me that much