Vista - Driver Problem with Canon LBP2900 Printer

Hi Folks,

Unfortunately, I encounter a problem with my brand new laser printer
Canon LBP2900. It is connected to my computer (Windows Vista) via an
USB cable and works properly as long as I am offline.
But once I go online, data transfer from the computer to the printer
will take several minutes. This phenomenon seems not to depend on the
size of the file to be printed. Pages are not printed stepwise (with
time interruptions between different pages) but in one single go once
printing is initiated. I suspected the firewall (Norton) to be
responsible for this delay. But even if I turned it off, delayed
printing did persist. I have already uninstalled the printer driver
and reinstalled when I was online with no effect on the slowed data
transfer to the printer. During data transfer, the program I want to
print from (Word, Adobe Acrobat etc.) seems to be pretty busy (task
manager will temporarily show 'Not Responding'). When I want to print
a PDF, the green status bar will rest at zero percent for ages. Then
(after several minutes) it will abruptly turn to 100%.
I would be very pleased if somebody could give me some advice here.
Thank you so much.

Regards
Ulf