Printer doesn't work (by 2 users)

I bought my laser printer last May, and until last week, it was working beautifully.
I also bought an inkjet printer second hand two weeks ago so I could print in colour now and then. I installed the driver from the site for the inkjet printer and it works great. To use either printer, I just used to unplug the usb cable from one printer and plug it into the other. Both worked fine, though it was a pain to unplug and plug, so I bought another usb cable for the inkjet. Both printers stopped printing. Little did I know that there is only one usb port for a printer. Fine, I figured that out, a little late....
Anyway, the inkjet printer works fine, but the laser printer won't work at all. It came with an installation cd which I have installed six times and uninstalled six times to no avail. It will not print a test page, but only an error page -

Position: )x42b (1067)
System: h6fwaim_mono/xl_image
Line: 132
Version: QPDL 5.04 04-25-2005

I have no idea what this means.
The laser printer will print a demo page, and as it was working all along with my Windows XP, it is definitely compatible, as stated on the demo page.
Anyway, I always change to the default printer, depending on which printer I want to use, and make sure it's online when I want to print, but I get a pop up saying to check the printing queue and try the trouble shooter, which I have countless times. I can't print in Word, Note Pad or anything. The laser printer is plugged into the proper usb port on my tower, the ink toner is new, as of two weeks ago, everything is plugged in, there are no paper jams,the usb cord works because I'm using it for the inkjet, and I use the same cord for the laser. I have no idea what to do and I'm at my wit's end. I've even gone to the Samsung website and downloaded the driver, but it still doesn't work. Is it the printer, or my motherboard?
I don't have a virus, I've done defragging, spy bot and ad aware, and I have Window Washer, if that helps.
I love my laser printer and bought one initially so I could print more without constantly running out to get ink cartridges.
If you can help me, I'd greatly appreciate it. I do need detailed step-by-step instructions though.