If mIRC is freezing, this sounds like the DDE freeze issue that users have reported in the past. If you are running a background application that does not handle DDE messages correctly, it can cause other applications that use DDE to freeze. As far as I know, there is no way to resolve this since it depends on other applications handling DDE messages correctly. You could try closing down background applications one by one to see if you can pinpoint which one is causing the issue.