You'll have to call Acer, Microsoft and maybe send in the laptop. There is a long discussion but I've found my answers which have upset some so I'll share but will not enter into any debate.
I unplug USB things, I'll even follow the Microsoft directions on how to install. I may even clone the drive prior to all this just so I can roll back and try again.
Frankly, WHY RISK IT?
Bob
I have now downloaded Vista Service Pack 1 two times - and both times it caused my computer to not reboot into Windows. I'm hesitant to install the service pack now, but I know that at some point it will be a prerequisite to other updates.
I had to complete a full system restore both times, so I'm sure you can understand my hesitation. To top it all off, I'm a graduate student in the middle of exams, so when my computer crashes, I go a little bananas.
Any suggestions to find the source of the crashing so that I can install the service pack successfully?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic