If you cant pull up a website, go to http://downforeveryoneorjustme.com to see if it is down for you or everyone.
If it is your website and it is showing that it is down for everyone, then you should contact your web hosting provider or a web designer (or developer) to look into the problem for you.
I will look at your problem and tell you what is wrong for free. Just contact me.
Posted in Maintenance Tips