Temporarily disable ACPI in device manager by replacing it with "Standard PC"
While I don't recommend using Standard PC for a laptop (poor power management), I'm pretty confident it will allow you to use your computer again.
How to do it?
Start / Control Panel / System / Hardware / Device Manager
Expand "Computer" and right click on on ACPI (Advanced Configuration blah blah..). Choose "Update Driver", select the manual option. And lastly, choose the "Don't search" option.
You should be presented with two choices... ACPI and Standard PC. The goal is change your power management layer to Standard PC which gives you "old-fashioned" IRQ steering. So select Standard PC and click next.
You will need to reboot Windows and this should work... But no guarantees can be made. ;) Also, this can render some computers / configurations unbootable, although this is a rare occurence. Be prepared to follow these intructions just in case the worst happens:
http://www.techspot.com/vb/showthread.php?s=&threadid=8356
Once you get your computer usable, you should change Windows back to ACPI. It will probably work OK again. Such are the splendors of Windows...