COM1 printer problem

Hello!
I have a problem with a ticket printer conected to a com1 port. In windows it works fine but the problem is when I start the computer. Right after boot screen, when windows loads, the printer starts to print strange and senseless characters, something like ????u0??0.
i've tested with several windows xp images, and they all have the same result. It prints a few lines, and then stops. After that, in windows, I can use the printer without any problem.
Any idea??

It's a game box, so the ticket printer starts when the game box turns on. All hardware components must start at the same time, so turning it off during booting it's out of discussion.
Any other ideas??

The problem was a serial driver from MicroTouch touch screen, that was sending information to com1 port, when windows booted up, to test if there is a monitor plugged in. I've disabled that and now all is fine.
In my future images I won't even install it.
Thank for the reply!