The biggest problem with connectivity is a bad DNS setting. Call your ISP and make sure your DNS settings are current.
Just so you know, every time you type in a URL like
www.msnbc.com or whatever your computer has to go to the DNS server you have specified to find out what the IP address is to get there. If you are using an old DND server or one that is flakey it can keep you from getting where you want to go.
Hope this helps...