I'm using wampserver. And I let my friends test the site that I made, by putting it online and giving them the ip address of my computer. The site makes use of a database. They were able to log in. But they cannot insert records on the database. There was no error but they said that it was very slow. Is there any way to optimize this one? Does my download speed of 45kb/s affect the speed of how they access the site? Is it really possible to pull of insert queries or other queries that modifies the database even if what I'm using is just an ordinary pc and not a full blown server?
There is no reason a desktop PC on a home connection could not perform database inserts/updates. If the bandwidth you supplied, 45kb/s, is true, that is likely the problem. 45kb/s is slower than typical dial-up (56kb/s). If you think the problem is network-related, try to use the website from a different computer on the LAN.
Secondly, there must be an error somewhere if it did not work. Either your users received a timeout/404/[any error] or there should be an error in Apache's error_log.
When users change the database through a website, the database sees only one host accessing it, localhost.