Port Forward Broken?

My port forward settings work fine for Minecraft, Apache, etc. I know because I've had friends on my webserver or my Craftbukkit server. Kudos, by the way. I've noticed that if my computer shuts down for some unusual circumstance, my port forward is messed up. I know because I have PortForward.com port checker. Whenever my friends are connected to my server(s), I check and the test succeeds. However, if my friends are unable to connect and neither am I, I test it and the port test fails on ports 80, 443, and 25565, ports that have worked on the previous day. So my question is, why is this caused, and how can I fix it? It automatically fixes itself over time, but I find it annoying having to wait an unknown amount of time until it is fixed.
Edit: Forgot to mention, yes, I allowed firewall exceptions. Yes, I've set a static IP address. No, my external IP address never changes.

 

Please tell me you're not running both a web server and Minecraft server from home.

 

Your internal IP has changed so the ports are not pointing to your PC anymore

 

Moved to the correct forum.

 

Just as Deckerz said.... Check your routers configuration. Most newer routers have options to "reserve ip"