Adding a Printer

I recently acquired a Sharp AJ-5030 all-in-one (prints,
fax, scans, copies). I have yet to see what all it can
do. First XP told me that the driver wasn't digitally
signed by Microsoft and i got the blue screen. Then I
downloaded an updated driver and software set from Sharp
that's compatible with XP. Good, right? The new
driver/software is installed fully without a problem.
When the printer is connected (with USB, the proper
driver is assigned to the proper port) XP won't boot.
Everything locks up. I have to disconnect power,
disconnect the printer usb, and the computer and XP boot
up fine after turning the CPU on.
If I then connect the printer USB after XP has loaded,
XP doesn't communicate with my printer. Has anyone else
had this problem? If so what did you do about it? The
machine is fine, I've used it independent of my CPU.
Faxes, I've printed test pages, etc. I'm at a loss.