There are 4 main reasons why you might have difficulties loading a web page:
1. The server on which the web page is stored is experiencing difficulties (i.e. it's down or overloaded). Try another page. If that works OK, it's probably a server problem (which you can't do anything about). Just a thought, though: If it's your browser's home page which is causing problems, are you sure that you really need to access this page? I'm frequently amazed at how many people wait for their ISP's home page (or whatever) to load up when they've no intention of using it! I always keep my browser's home page set to 'blank page'.
2. A bottleneck occurs on the path between the web server and your ISP. Once again you can't do anything about this.
3. As Dagman has suggested, some firewalls (especially Zone Alarm) can block some sites for no obvious reason. Check your firewall's log. If you see that traffic has been blocked from the site which you're trying to access, you'll need to adjust the appropriate settings.
4. Your PC experiences a problem communicating with your ISP's domain name server. The software which connects your computer to your ISP (whether it's 'dial-up networking' or broadband software) has a default TCP/IP setting of 'server assigned name server'. You can change this to 'specify name server' by going to your ISP's website and finding out their primary and secondary DNS numerical addresses. You then need to go into the relevant software and enter this information. (If you need instructions, I can tell you how to do this for a dial-up connection but I'm not really sure about broadband). Sooner or later, most people switch to 'specify name server' because this gives a more reliable connection.
Chris