I have been having troubles ever since I have signed up on the internet with not being able to get to all web sites. I have the same ISP at work, and things are great there. I even got a new computer a few months after being on the internet, and that computer does the same thing, even though it has a different browser and a different Mac OS. I have checked preferences and everything. Does anyone have a suggestion??

This could be just a matter of changing your settings...
When posseble use your ISP's proxy settings in your browser's preferences (Netscape: preferenses > advanved > Proxies > select "automatic proxie con..." and type in the proxie URL (your ISP should tell you).
Then press the 'Reload' button and enjoy jourself!!

If that doesn't do the job or if your ISP does not have this service then check your Primary and/or secondary (name sever addrr.)Domain settings and 'Search Domain' in TCP/IP (a control panel), again your ISP should be able to tell you what this should be set to.
It is best to do this while talking to your ISP's helpdesk person, he or she will talk you trough it.. that's there job!
When your work is using the same ISP then it is posseble to compare all settings there with yours at home...
Good luck!!