Hi, I've just ordered a MBA revB and I'll have 14 days to check it for "problems" such as dead pixels, thin grey lines on the screen, high temperatures, etc before my return period expires. I've never seen a dead pixel and I can't see any of the thin grey lines in the photographs posted to this forum...so are there any tips for how to detect these problems? e.g. is there freeware to search for dead pixels? Thanks!