I had a problem which I found the solution. Maybe this can be extrapolated to other connection problems. It is not specific to MIRC but to all IRC clients.
Thread here It might solve a lot of your connections problems if you have trouble under XP. It is due to Winsock which configuration has been corrupted/modified. To fix it,
"Keep somewhere your IP configuration for Internet. Then you will need to repair/reset Winsock configuration.
To perform this, download
Winsock XP Fix 1.2Run it. Then you will reboot your computer. Configure your IP properties (since it's been cleaned) and the problem should be gone!!!!" :tongue:
Please reply if it has helped to fix some of your problems