IP Address Problems???

I recently got a virus and had to reinstall Windows XP. When I got done installing it, I went to all of my freebie sites. I later realized that my computer how had a different IP address. However, this computer, as well as two others in my house are all run off a router. So, my question is, would I now have a conflict with these sites, as I know its a bad idea to log on to them with a different IP address. Or, would there be no problems since the external address from my computers router would be the same before and after the reinstallation of Windows. I really need some help with what to do about this! Thanks!

Your computer's private LAN IP address is not what the freebie sites (or any internet site) care about, they care about your internet IP which is on the internet facing side of your router. Reinstalling Windows isn't going to change the IP address that your router negotiates.

Home internet IP's change all the time, and it's beyond your control, so I wouldn't worry much about it. Freebie sites aren't looking at your IP changing, they're looking at other folks signing up from the same IP.