Install Nircmd in Windows
Next button
nircmd sendkey 0xB0 press
Previous button
nircmd sendkey 0xB1 press
Play/Pause button
nircmd sendkey spc press
Stop button
nircmd sendkey 0xB2 press
Volume down
nircmd sendkey 0xAE press
Volume up
nircmd sendkey 0xAF press
Command reference:
http://msdn.microsoft.com/en-us/library/dd375731