It would be helpful if you could reply back with your brand and model number, but I can give you a good answer without it.
First of all, this won;t be a problem with the fuse. When a microwave's fuse blows, the unit will be dead.
This is usually caused by either a bad door switch, a loose door switch mount, or a problem on the control panel.
Even though a door switch clicks, it may still be bad inside. Its continuity must be checked.
Door switch or mount trouble can be caused by slamming the door or by opening the door while it's cooking without hitting the Stop pad first.
If you someone you know decide to look into it, we have critical information on safety, disassembly and door switches at our site, and our link is at our listing here on FixYa: http://tinyurl.com/yzjozk
You can find helpful exploded view diagrams and order parts by entering your full model number here: http://tinyurl.com/gv383
If yours is not listed, please reply back with your brand and full model number.
If you think the problem is on the control panel, which we repair these nationwide by mail for $39.95 postpaid.We're happy to help and we appreciate your thoughtful rating of our answer.