Is there a way to use either ASP or JS to prevent someone located in Nigeria, Ghana, and Sierra Leona from seeing my site? There are many panksters that go to my site and play with the online ordering system. Is there a way my server can recognize the IP address of the visitor?

If this is possible, how can I determine which IP's pertain to those countries? Thanks!

Do you have a control panel? Also, check out the server logs to get their IP addresses.

There is no guaranteed way, because people can use proxies to fool your IP detection system.

You can use a service such as www.whereisthatip.com

There has been a discussion on this topic before at WHT.
Use the search and you should find the topic.
Just a note, you cannot completely block the entire country with a fool proof procedure.

Cheers.
Kavs

Here it is -
http://www.webhostingtalk.com/showthread.php?s=&threadid=310640

Cheers.
Kavs