weird printer behaviour!

[az0000000]

Hi everyone.
I use Windows XP Pro and I have Canon i560
A strange think has happen recently to me.
My printer one day refused to print from any window application including notepad. Worst than that, it isn’t able to even print a test page. I checked absolutely all settings and wires. I reinstalled drivers from zero. Nothing helped.
Now the most interesting part comes: I can easily do all maintenance jobs, which means computer can freely communicate with printer.
So I am completely puzzled… Computer easily communicates with printer to do all maintenance operations but it isn’t able to even print a test page…?
How the hell can that be possible?
Windows applications behavior when trying to print is like there isn’t any printer installed or like there is configuration problem.
Recently because of worm that works through avserve.exe I installed a fresh patch from Microsoft that blocks some kind of ports so the virus wouldn’t be able to spread. Could that patch somehow block the printing capacity of my printer port? I use LTP port by the way.
Tanx a lot!