I have an HP Pavillion HPE (h8-1380t) running Windows 7 Pro (64-bit) and I have a headset plugged to the top of the computer. FYI, on the top, the computer there are 4 ports: headset out, headset in (mic), and 2 USB ports. Here's what is happening:
a – I can listen to YouTube videos.
b – When I use Skype, my voice is heard (i.e., the mic works) but I do not hear anything.
I tested the speakers using Tools > Options > Audio Settings > Speakers (which is set to Communications Headphones, IDT High Def..., Auto Volume) and I hear the sound.