I recently tried to upgrade a Toshiba Satellite laptop (Model A35-S159, running Windows XP Pro SP2, fully patched, with BIOS flashed to the latest - September 2004) to Windows Vista Business Edition.  Apparently, I'm one of the many people lucky enough to have a computer that, while being ACPI compliant, isn't quite ACPI compliant enough for Windows Vista.  I'm not even sure what that means. 

I ran Microsoft's Vista Upgrade Advisor, and the machine passed with no problems.  I ran the upgrade, and that seemed to go great too (though it took a long time).  On the first boot (which should have been into Vista), I got the popular Blue Screen of Death telling me my system's 'BIOS isn't fully ACPI compliant'.  Great. 

The only bright spot (if you can call it that) is that, if I'm quick, I can catch the boot screen as the laptop powers up and choose 'Earlier Version of Windows', which will take me back to Windows XP.

But that just gets me back to where I was before I ever tried Vista.  I can't find any hope on the web, except Microsoft saying the vendors will have to update the BIOS...that's apparently not likely in Toshiba's case, as they say right on their web site they won't support Vista except on PC's with the Vista Capable logo.  From their support web site:

Q: If my Toshiba computer does not have a Windows Vista Capable sticker, does Toshiba offer drivers and BIOS upgrades for Windows Vista?

A: No. Toshiba offers Windows Vista drivers and Windows Vista-compatible BIOS upgrades for computer models that have a valid Windows Vista Capable sticker. It may be possible to upgrade to Windows Vista on some Toshiba computer models that do not have a Windows Vista Capable sticker, but Toshiba cannot guarantee that all features of the computer will function correctly after the upgrade. Microsoft’s Windows Vista Upgrade Advisor may be able to indicate whether or not your computer has the minimum hardware requirements for Windows Vista, but a positive report from the Upgrade Advisor is not a clear indication that the specific features of the computer will function correctly after an upgrade to Windows Vista.

I'm not much for conspiracies, but this stinks of 'plot to make people buy new hardware'...