If 10.5.1 is buggy, is it possible to go backwards and reinstall 10.4.10? If so, does it keep all your apps, docs, music/pics, etc? How hard is this to reinstall and how long is it? And where do you get the 10.4.10 disc? I think I have a disc that came with my macbook in a box- is that an OS disc? And if it is some old version of OS, does it automatically update up to the latest revision of 10.4? Thanks!