My site is offline

[syrdax]

Hello. I'm sorry if this is resolved but I truly searched for a solution for this but I didn't find any solution for my problem.
I'm using Xampp 1.7.7 on Windows Xp. I have a couple of websites that were working just fine. Somehow my ISP ended our static IP service (we didn't know for a couple of weeks), since then the websites stopped working. We contacted ISP to have our static IP service back which they did, however the websites still don't work. I don't understand much how things work, I started using Xampp because generally is like fire and forget and don't have to do coding and stuff, so I've searched around for a solution but searching for the exact problem isn't really easy when there are a lot of solutions that are kind of similar to my problem but don't apply.
I didn't change anything to configuration, I still have the same virtual servers for our sites, listening to port 80 (free and accessible according to openport), localhost loads fine, but, we can't access the sites from outside.
I tried to find if there's something somewhere to change our external IP but I couldn't find anything.
I'd appreciate any kind of suggestion.
Thank you.