Problem with a shared printer

Hello everyone,

How are you guys doing?
My name's Tuan Nguyen.
I've been dealing with a difficult situation between computers and a shared printer. Please help me out and I will appriciate that. Thank you in advance.
Problem: I have 4 computers are connected on the Local Area Network via a Wireless Access Point. The first one is used wired connected on the WAP and the rest of them are used wireless card to access the Internet and share files. I have a laser printer which made by Dell company. This is a shared printer on the LAN and connected on the first computer. I was be able to share this printer for the three computers and worked fine. Unfortunately, when I tried to reboot the three computers, they could not use a shared printer anymore, and I needed to reinstall and install the driver back again. From that point, the three computers can use a shared printer as long as the three computers must be turned on 24/7. Does anyone have any ideas why I am having this problem? and suggestions? not only with Dell laser printer, but I have the same problem with some printers, such as Epson, HP, and Lexmark.
I use Windows XP Professional with SP2.

Thank you,
Tuan Nguyen