I have an old computer that has no hard drive. It has a 3com NIC 10/100 with a boot rom on it. How can I boot to the server and run all files directly from the server?
Yes.
Your NIC should have a 3-pin (or 4-pin) connector on it. If so, then this NIC is boot-capable. Your motherboard also has to have this capability also though. The board should also have to other end 3-pin (or 4-pin) connector. The cable that would go between the two should have been included with your NIC. THen you would have to connect the 2 and enable boot from network in your BIOS.