First, because you are going online from Wi-Fi hotspots, I would advise you to take the following precautions. Make sure that your computer network setting is set as 'Public'. This will prevent others from tapping into your session and will help prevent attackers and hackers. It's directly under the section "View your active networks" in the area where you click to see the map. Just click the name of your modem/router and make the appropriate change from there. By the way, if you are set as 'Public' already, the compter will not allow you to see a map. Also, make sure you have good computer security installed and running in real-time (resident mode). There are plenty of good ones that you can buy or download for free. Have a Anti-Virus product, a Anti-Spyware Product, and most importantly a Firewall product. Some products conviently include all 3 into a suite. When looking for security, try to find one that has a "safe search" web feature that will notify you if it is safe to go to certain websites and if you accidently do, will stop you and warn you before proceedng to the site. Also, try to find one that informs you if something is trying to make changes to key registry areas or trying to change your browser homepage.
Second, click 'Start', type "cmd" into the search box. Click on "cmd" or press [Enter]. Once the dark window comes up, type "ipconfig/all" and pres [Enter]. Your Private (Internal) IP Address of the computer will be listed next to "IPv4 Address". Your Public (External) IP Address that the ISP uses for your online activity will be listed next to "Default Gateway". Yes, you have two IP Addresses. I was surprised to learn that I did. More than likely, only your Private IP will have changed if there was a change at all. If you had your IP Address written down, compare it and see if there was indeed a change. You can also go to a wesite that will show you your IP Address and your geographical location. Try ip2location.com or whatismyipaddress.com
Third, I'm no tech. Just contact your ISP (Internet Service Provider). Tell them what happened. They would know how to handle it.
Oh. One more thing. Very important. Be careful following online steps, like how-to videos submitted on youtube, about making serious changes to your computer. These changes could lower your security and allow someone to hack or attack your computer.