Yesterday I installed Xampp, and it couldn't install apache and mysql because the ports were closed. So I did a search, and someone recommended uninstalling Xampp, then close all processes from programs not needed, then install again... and it worked perfectly. And I was able to make use of everything.
After switching my PC on this morning, Apache didn't want to connect. After trying a few times, I uninstalled, and now both Apache and MySQL doesn't want to connect because of closed ports, and I already did what I did yesterday, but it didn't work this time.
I also followed this over here http://www.dummies.com/how-to/content/how-to-open-a-port-in-the-windows-7-firewall.html
to open the ports needed (80, 443, 3306), but that didn't do the trick either.
One more thing... After uninstalling, I couldn't get the xampp directory removed, there was some files left there, and I just couldn't get them removed...
And, I use Windows 7, with windows firewall.