Default Printer selection keeps changing

[Bobster55]

I am running Windows XP on a Dell desktop.  THis is hardwired but I also run a laptop through my wireless router.  I have multiple printers installed, but have one selected as my default printer.  Whenever I reboot my computer, when it comes back up, the default printer selection has "automatically" changed to another printer.  If I manually change it back and reselect the default, it stays that way until I turn off or reboot...then it changes again!

[Carbon Dudeoxide]

I don't know what the problem may be, but I thought I would ask a question.

Is this a recent problem or has it always happened?

What happens if you set it as default, print something (to make sure it works) and then reboot on the spot. Does it change?

[Bobster55]

Actually, this began after I installed a new printer (HP L7500 all-in-one).  I DID check all the startup menus, setup guides, etc. to make sure it didn't automatically make it the default (Obviously, I missed something!)  This IS the printer that the default switches to.   
It doesn't seem to matter whether I print with the 'non-default' printer or not...it only changes when I reboot.

[Broni]

have one selected as my default printer

Where exactly do you go to do that?