I am in work right now so will not be able to test anything until later.
We'll be here...
If you could find which file is being scanned and freezing the computer, it will help.
As a workaround, if you're SURE that the file is CLEAN (not-infected), you could use the Exclusion lists:
For the
Standard Shield provider (on-access scanning):
Left click the 'a' blue icon, click on the provider icon at left and then Customize.
Go to Advanced tab and click on Add button...
For the other providers (on-demand scanning such as the screen-saver or the Simple User Interface):
Right click the 'a' blue icon, click Program Settings.
Go to Exclusions tab and click on Add button...
You can use wildcards like * and ?.
But be careful, you should 'exclude' that many files that let your system in danger.