In some computers, especially older systems and those with slower peripherals, it may be necessary to delay the loading of a specific Windows NT service for the computer to boot properly. Or you may want to ensure that one service has started and is available for use before another for troubleshooting purposes. This can impact such issues as a domain controller, which cannot access the network where a protocol, or a service such as DHCP, attempts to load BEFORE the network card has had a chance to be bound

You create dependencies (that is service A can not start until service X has started, ie there is a service dependency ), you use the DependOnService value. For details see:

Q193888 - How to Delay Loading of Specific Services
Q115486 - HOWTO: Control Device Driver Load Order
Service Group Order