regarding replacing I/O board?

I'm assuming this is what I need to do with my macbook. For years the power light fades and pulsates from green to amber, not charging the battery and then magically starts working again within a couple hours. It always worked when I took it to the Apple store. Over the last year, it has become more common. A couple weeks ago, it was down for 15 hours and magically lit up sometime overnight. It went down again 2 days ago and won't come back up. I took it apart last night to see if the connector looked loose, but it didn't. I read someone's post about how they replaced their I/O board and it worked for a short time and then stopped working again.

Before I spend $100 buying a new board, is there any reason theirs would work and then stop, other than a faulty board? I don't remember if they said where they bought it but I see one for sale on this site with a 6 month warranty.

I would rather put the money towards a new computer, but I can't afford to update my Adobe software right now. And if I can't use it, I can't make any money.

Thanks for any comments, suggestions or warnings.