One of my Windows 7 PCs running Avast Pro now has Avast Secure Browser after a recent update. But another one, though showing as up to date, still has the old SafeZone browser, on which Bank Mode has stopped working. I downloaded Secure Browser and tried a manual installation, but that does nothing - no window pops up although there's a process for it visible in Task Manager, apparently using CPU time. What might be stopping this from installing?