Open Spybot, then leave it alone
Open Task Manager, and go to the Processes tab
Right-click on SpybotSD.exe, and choose "Set Affinity..."
On the box that comes up, check/uncheck boxes so that ONLY "CPU 0" is checked.
Go back to the already-open Spybot, and run a scan. It should complete without hanging or losing responsiveness.
More info:
*forums.net-integration.net/index.ph...ndpost&p=113214
*forums.net-integration.net/index.ph...t=0&#entry85933