Question : Problem: "HP Digital Imaging Monitor has encountered a problem and needs to close." and HP device not detected HP Solution Centre will now close

These 2 messages may be interrelated. I am running Windows XP and the Printer is not networked

Answer : Problem: "HP Digital Imaging Monitor has encountered a problem and needs to close." and HP device not detected HP Solution Centre will now close

have you tried uninstalling all of the HP software and then reinstalling it?
If you have an Anti Virus program, check that the online scanner is set to exclude scanning of the HP software directory.
Try also downloading CCLEANER from here : www.ccleaner.com
When you install and run CCLEANER it will clean up all temporary files and it also has a registry cleanup option which you should run to sort any missing or corrupted registry keys.