Precision 3650 Tower, Headphones NOT detected, Sound distortion on Right channel

Hi.

From day one, my 3650 tower had occasionally little distortion on the right channel and never detects the insertion of headphones plug.

I fiddle with the driver and somehow it worked, sound was crystal clear and headphones working just fine. UNTIL restart...

Again the same and do not know how to correct the problem.

I'd appreciate any help on this. 

Really, what audio card/chip this tower has? Can I update the driver from Realtek? And which one? 

Last, the headphone icon has a red down arrow and Configure is greyd out.

Thanks,

Ioannis