can upgarde the RAM and hardrive, try click here but thats about it. For the sound try plugging in headphones to see if you get the same response, or a spare set of speakers.
It could be that you just need to adjust the volume control, do you have realtech driver it could be that you need to adjust the volume control on there instead of the windows volume control.
If that all fails then its beyond me, could try taking it back to get a refund if under warrenty.
Also when upgrading u need to know is the harddrive pata or sata. I hope this helps