I'm having a problem where windows restarts by itself while using mirc. But it does it when every it wants after 10mins 30mins or 3 hours and I'm not sure why.

Does anyone have any ideas?

The only time I've encountered this, and it has nothing to do with mIRC, is when the Windows Auto-Update has downloaded and installed an update that requires an automatic reboot.

no I've got automatic updates turned off