You can use the install packages screen and filter the packages to see if they still need to be installed. If you want to check if Apache is installed, go to http://localhost - you should see a test page if Apache is installed and running. You may need to start it, you can do so from the DrakXServices screen in the Mandrake Control Center, there you can also choose if it should start at boot. If the httpd process is not in the list, it appears not to be installed and you should be able to reinstall it from the packages screen.
As for the MySQL server, you can check if that has been installed by opening terminal, login as root and go to your mysql/bin dir (not sure what the default folder is of the Mandrake package, I installed manually) and type './mysqld_safe'. You should see something like this:
Starting mysqld daemon with databases from /usr/local/mysql/data