On top of what the others have stated. MS backed a lot of large institutions into their upgrade agreement (fancy name escapes me now). This just so happens to coincide with their "November" for institutional purchases ship date. I know that a lot of these folks are pretty upset that their agreements didn't really cover very much "new" software. If there are many defections there, then the whole thing starts to unravel.

Microsoft is not exactly a very popular company at present to begin with. In this society, it is sport to watch heros fall. Combine that with price/earnings that have had the rosiest of rose colored glasses on since the mid '90's and you have a recipe for perpetual $20 - $30 share prices (for at least the next few years). I have been tempted to buy the old MS stock a few times in the past few years, just based on the upside (another potential $80 plus per share ride), but I don't feel real warm and fuzzy. It could happen, but I wouldn't bet on it.