Graphics Lockups..

Yes, it's possible to have to same issue especially if you received the 8600M GT again as the fix.

For this case, I'd demands a replacement machine. Basically take it in to be fixed at an Apple Store or call AppleCare and have it escalated.

 

Apple promised to cover this problem for a specified number of years past the warranty, and it applies to all 8600M GT machines.

 

Yep you can get it repaired again, they extended the warranty for GPU problems on the 8600GT to 4 years from purchase date.

I went through a similar problem with my late 2007 macbook pro, I had 2 logic board replacements (for GPU issues), seems the "rev 2" version of the 8600GT that was supposed to fix the problem is not reliable at all.

On the second replacement (third failure) they damaged some other areas of my computer so Apple ended up replacing it with a new 15" i5. I have to say I'm glad to be rid of the 8600GT.

 

I very much doubt they will issue a replacement after having one logic board replacement, Apple will request another chance to fix the problem first.

I had a similar opinion in that I did not want another 8600GT after having 2 fail already (the original and the replacement), but I was assured this was very unusual and that for anything else to happen, I'd have to go through another repair cycle first. Had my computer come back without the other damage I mentioned, perhaps everything would have been OK, but I highly doubt it with both the original and a rev2 not correcting the problem.

If you do speak to Apple, make sure you go through to customer relations, they seem to be the highest level a customer can go to without having to write to Apple corporate offices.