you have a bad download of the newest WMP or it got corrupted somehow.

Go into control panel and your windows setup and uninstall the media player, then reboot and reinstall it, then go get your upgrade again to the newest WMP

Changing the alternator and battery should have no effect on the systems you have mentioned.

Most likely your turn signal switch and wipers are all in the same switch on your steering colum and that switch has come unplugged or needs to be replaced.

Without perfoming tests for continuity to see exactly where the power goes and doesnt go, it's really hard to say what the problem is.

There are a few model GM's with tilt steering that have a problem that after many years of useing the tilt up and down, it can loosen or uplug the wiring in the column that goes to turn signals and wipers.

In my experience, its highly unlikely that both the turn signal switch which is located in the actual steering wheel housing ( the turn signal lever you push up or down is only a rod that activates the switch further in ) AND the wiper switch which is actually built into the turn signal lever ( and no where near the actual turn signal switch located inside the steering column ) , are both gone at the same time.

My best guess would be that the wiring harness has come unplugged to them which if your lucky may be under the dash and if unlucky located inside the steering column itself and requires special tools and knowledge to get at as a puller is required to remove the steering wheel and special knowledge to ensure the airbag doesnt deploy while your working on it.

if you know how to test for continuity , the first test would be to see if there's power at the wiper motor when the switch is on and then at the fuse box for the wipers... my best guess again would be none at the wiper motor and power at the fuse which means the problem is between those two areas and the only component between that , is the switch.

do your four way flashers function ? if they do this would indicate that the wiring going to your flashers is not at fault and give a larger percentage that the problem is the switch or the switch has come unplugged as these are two different circuits under the dash which run into the same wiring harness once under the hood of the car and go to the flashers