For a stable and robust web-server, LAMP is the best combination possible. The LAMP system comprises of: Linux, Apache, MySQL and PHP; Linux is the base or the Operating System software on which the others will run; Apache is the actual web-server software; MySQL is the Structured Query Language or the database software; PHP is the Hypertext Preprocessor for dynamic web-pages.
All the above software products are open-source. Meaning, you are free to use them without having to worry about copyright infringement. The only restriction is you are not allowed to modify the source code of the software. A word about the hardware requirements for the LAMP; people have been known to run LAMP successfully on 128MB of ram on a 800MHz CPU, using a 4GB Hard Disk. Such low configurations may not be commercially available any more, so we can safely say use anything available as long as it is robust, since it is the life of a server what we are putting at risk.
The first step will involve installing the OS or the Operating Software. This is as easy as sticking the live-CD/DVD of the OS into the drive and booting up the PC. You will see the OS running from the CD/DVD and asking you if you want to install on the HD or the hard disk. Say yes, and the wish is fulfilled. Well, if you need to do something special like partitioning your HD, etc., you may need to explore first.
Before we start installing and setting up the others, we need to set up the OS properly. Since we are going to make changes to the basic OS, we need to assume the status of the Super-user; in other words, 'login as root', and remain so until all the installation is done. If you do not have access to the hardware from a keyboard, or you are doing a remote login, use Secure Shell, and not telnet; not to compromise the security of the server. Depending on the Linux distro you are using, these names may differ somewhat.
Again, depending on the Linux distro you are using, you may decide to install the standard versions of Apache, PHP and MySQL, in which case, there is no need to uninstall anything. On the other hand, if you are very particular or need to tweak the software to extract maximum performance, you may decide to install after compiling the source code; in which case, you will need to uninstall the standard versions which are given with the OS, download the correct source code versions suitable to your OS, and begin compiling. Whatever course you choose, you will need the C++ compiler. Check for and install if necessary, gcc and gcc-c++.
The next step is to check and if necessary, download the Apache, PHP and MySQL from the repository of your distro and install. In case you are going to install after compiling, get the source code for Apache, PHP and MySQL, unpack and use the standard 'configure' and 'make' compiling procedures, to install. Execute the install procedure sequentially, starting with MySQL, then Apache and finish with PHP.
Ensure the security by following standard procedures, see references below.
Check up everything. You are done!