Intermittent Sound, running finger over speaker/mic inputs [XPS M1710, Vista SP1]

Need some input from XPS M1710 owners anyone else running into intermittent sound issues after installing Vista SP1.

Initially upgraded to SP1 via Windows Update. Everything was fine and then last week I started having sound issues (sound would just cut out). In addition to the sound problem, I found when waking the laptop from sleep by opening the lid, my graphics card would change resolution to 1024x768. Windows would lock up a short time after this.

Checked Event Log and nothing was found to indicate a problem.

Contacted XPS Support. Motherboard and CPU replaced.

Same issue. Wiped Hard Drive and clean install of Vista. Ran into trouble upgrading to Vista SP1 due to Sigmatel driver and was finally able to install SP1 by using the following process:

1. Wipe HD and install Vista using retail Ultimate DVD.
2. Update all Dell Drivers except for Sigmatel.
3. Install SP1 using standalone SP1 installer (bypassing Windows Update).
4. Installed Sigmatel R171788 drivers from Dell

Now, all seemed fine. Last night the sound problem returned. I grabbed a pair of headphones (Sennheiser HD280Pro) and went to plug them in to see if the speaker output was also dead. As I was feeling for the speaker jack, the sound came back. I ran my finger back and forth over the jack and the sound returned!

What the hell is going on with this system?? The motherboard was just replaced so it cant be the board, right?? This problem was happening on the original board and now also the replacement.

I'm about to call Dell back and demand another board be sent out. The power jack is also loose.

Dell is sending out a tech to replace the 7950GTX but perhaps I need another MB...

Thoughts? Anyone else seeing this? Can someone with sound isues see if running a finger over the speaker/mic jacks causes your sound to return?

Thanks.