Installing LPR Printer on Vista and XP

A little back ground.  I work at a major university and we have about 18 different printers in labs that are creating a Visual Basic 2008 program that will allow the user to choose any number of printers to install on their laptops.  I have several problems I have can't seem to figure out. 
 
1)  How do I check to see if the LPR port and Printer have been installed?  I want to check for the port and printer seperatly and I can do this in Objective C on the Mac with the grep command.  Is there an easy way to check for a specific printer and pull a single word to compare in an If statement?
 
2) I know the command prompt command to turn on the LPR on Vista and XP, but how do I check to make sure it is installed before I try it?
 
3) I am having issue with the rundll32 printui.dll printuientry command. It works on the XP machines, although I get an annoying continue to install hardware, how do I bypass this?  And why does it not work on the Vista machine?  It looks like it run, does not give me any errors what so ever, just nothing.
 
Here is the command:
 
printui.dll, PrintUIEntry /if /b "CSE-211-CLQ" /f "C:\INF_Files\7760.inf7760.inf" /q /r "CSE-211-CLQ" /m "Xerox Phaser 7760GX PS" /z /u