Lately my early 2008 MBP boot with kernel panic whenever I carry it around but not when it's sitting on my desk. Is it a symptom of man board failing or what?

I had it's main board replaced 3 yrs ago with AppleCare when it developed graphic card issue. Now I wonder it's time for an another mainboard problem.

When I get kernel panic as it boots, I have to restart it with power button and then it boots up normaly, everytime! Other than that there is no issue with the macbook pro... I have backed up the hard drive in case. I'd like to know whether it can be repaired.

Thank you.