As we all know, Mac have less problems than most PC, but it does happen. If you ever experience such problem, Apple just released a step-by-step procedure to isolate the origin and potentially fix it. The new article is in the knowledge base: http://support.apple.com/kb/TS1388?viewlocale=en_US
However, in most cases, the advise is to reinstall Mac OS X the same rescue advise made by Microsoft for years. Luckily, one can find less extreme procedure in Mac-dedicated websites (such as our a href="http://forum.hardmac.com" target="_blank">forum), or even in Apple knowledge base if you scroll-down the page mentioned above.
[translation by Linathael]
