How do I install a network printer for all users on a Windows 7 computer?

You can use the prnmngr.vbs script.

It's located in %SystemRoot%\System32\Printing_Admin_Scripts\[language] for Windows 7. For XP it's located in windows\system32.

To add printer for all users you use this command:

cscript prnmngr.vbs -ac -p "\\server\printer"

When you add a printer as a local printer all user can view it.

I found this here http://www.windowsnetworking.com/kbase/WindowsTips/Windows7/AdminTips/Admin/AddSharedPrinterasaLocalPrinter.html

In Windows XP:

1. Click Start > Printers and Faxes.
2. Click Add a Printer on the left pane.
3. Click Next.
4. Select Local printer attached to this computer and click Next.
5. Select Create a new port, select Local Port for the Port Type, and click Next.
6. For Port Name, enter the network path to the printer by entering two slashes, the computer name or local IP address of the PC sharing the printer, and then the share name of the printer. For example “\\dellpc\hpprinter” or “\\192.168.1.100\hpprinter”
7. Select the printer and click Next. If the exact model isn’t listed, try the closest model number or a generic printer.
8. Follow the rest of the wizard.

In Windows Vista and 7:

1. Click Start > Devices and Printers.
2. Click Add a Printer on the top.
3. Select Add a local printer.
4. Select Create a new port, select Local Port for the Port Type, and click Next.
5. For Port Name, enter the network path to the printer by entering two slashes, the computer name or local IP address of the PC sharing the printer, and then the share name of the printer. For example “\\dellpc\hpprinter” or “\\192.168.1.100\hpprinter”
6. Select the printer and click Next. If the exact model isn’t listed, try the closest model number or a generic printer.
7. Follow the rest of the wizard.

It is important to remember that shared printers are saved on the user profile. This means that when you connect to a "shared" printer (through the wizard), only the user account that connected to it will have access to it.

Local Printers, on the other hand, are global devices that are viewable by all users on a computer. These use "local" TCP/IP ports to connect to a "real" network printer.

So with that all said, let me answer your question. To have a shared printer "showup" for all users, you will need a system in place that will add the printer for each user as they log in.

This is done by crafting a logon script. There are a number of methods and languages you can use, and you have to find the one that works for your environment. Here are some resources that I have found that might help:

Deploy Shared Printers using Group Policy

Windows Logon VB Scripts

Powershell Printer Port add discussion

Hope this helps!