I have a 10yr old house. On one circuit, I have a microwave, a fridge, a deep freezer and my front proch/xmas lights. Everything thing is fine until I heat something up in the microwave and pop goes the breaker. Can I just get a larger amp fuse or is that dangerous? Please help.

No... that would be dangerous... violate code... and maybe even be a reason for your insurance to deny a claim if a fire resulted as a resut.

The breaker size isn't determined by what you are trying to run... but by the actual size of the wire on that circuit. As that is what determines the maximum safe load limit.

NO, NO, that's how houses burn down. That 1 circuit is overloaded. The solutions are to move the appliances around to reduce circuit load or run a new line for the MW.