T-mobile Wing speaker problem
I had this happen after around 14 months of usage. Mind you, I changed the registry value in the first week I had it so that the speaker volume was increased to a hearable level, so perhaps I just burned out the speaker after having it on high for so long.
Anyway, I went ahead and bought the replacement part (HTC Wing P4350 Loud speaker ringer buzzer parts OEM USA) from eBay for US$8 including shipping, and I put it in the other week and it worked fine! I was so happy! You need the appropriate star mini screwdriver (my friend had one), and you undo the four screws after taking off the battery cover and battery. Plus you need to be Ok with unscrewing through that little Void sticker on one of the screws. After that, the enclosure where the speaker is will lift out, and the speaker itself will come out as well, it just sits in there connecting with the contacts on the board. Anyhow, I took my old one out, plopped the new one in, and put it back together. Turned it on, and voila! My speaker was working again.
In case it helps, when mine went out I noticed some crackling coming from it off and on for about a day before, and then on the day it went out the crackling was loud and distorted the music I was playing. After a couple of minutes it stopped playing altogether, restarts didn't help.
At least this problem is fixable, but first determine whether it is the speaker or a driver issue. Try to play a file in Windows Media Player - if it looks like it's playing, and there is no sound (and the Windows Media Player sound is turned up AND your phone volume is turned up), then it's most likely your speaker. Good news, you can fix it. Good luck!