HI
I have an ASUS P5VDC-TVM with all the audio drivers installed, now the front speaker jack is not playing any sound, while the rear jack and mic jack are 100% working.

What might be the problem?

Audio chipset - Realtek ALC655 6-channel codec

I'm looking at the motherboard user manual right now.

The front audio jacks connect to a front audio header on the motherboard.
FP_AUDIO

(Header - series of contact pins on the motherboard. This time for the front audio jacks.
It is at the bottom left corner )

If the cables from the Front Audio header to the Front Panel, are not loose, you have a bad audio header.

If you have an open available PCI slot, you can use a Sound Card. Eliminate your problem.

[ PCI slots are White. You have three. Located at the bottom of the motherboard under the CMOS battery ]

You have 6-channel audio available. Excuse me. You did.

Your replacement audio should be at least 6-channel also.

Just an example, not a recommendation,

Diamond Xtreme Sound 7.1/24 bit Sound Card at TigerDirect.com

Regards,
joecoolvette