I saw that 69 viewed this post and no one answered. so my frustration led to the extreme and I finally figured it out!
To anyone else having the same problem, my problem was I had a dynamic IP address. Somehow my settings in my router changed, leaving me with a different internal IP. My IP to connect to was the same, however my internal IP changed. (I'm and idiot and didn't realize this the first time I saw it.)
To stop your IP from changing you must create a static IP (sounds complex, it's not!)
Open Command Prompt and enter "ipconfig /all" without quotations. This should bring up your computers details. All we need are the Subnet Mask, Default Gateway and DNS Servers.
Now open Control Panel, and go to Network and Internet. I'm using Windows 7 so I apologize if our operating systems are not exactly the same. Under "View network status and tasks" you can find Change Adapter Settings.
In Change Adapter Settings, locate your network, and right click and click the properties tab. A window should pop up and a list appear with the items your network uses. Highlight the "Internet Protocol Version 4(TCP/IPv4)" and click Properties.
This should open another window, and either "Obtain an IP address automatically" or "Use the following IP address" should be marked. If you already have "Use the following IP address" marked with an IP already entered, then THIS IS NOT A SOLUTION FOR YOU!
Select "Use the following IP address". Now we need to use the info you obained using command prompt earlier. First, you need to create an IP. IMPORTANT: Do NOT use your Default Gateway IP! You must change the last number of your default gateway. (example: 191.153.1.1 is my default gateway, an acceptable IP would be 191.153.1.10) the last number must range from 1 to 254.
With your new IP, you need to confirm that this is the IP used when port forwarding! You may need to change this on your router control panel. (I had to)
Now enter the other information into the correct places. Enter the Subnet Mask, Default Gateway and Preferred DNS server. (You do not have to enter an Alternate DNS server).
Now click OK and verfiy your IP in the command prompt by entering "ipconfig /all".
Everything should be the same except the "IPv4 address" which should read the IP that you created.
I hope this helped because it fixed my problems. Good luck!