It could be a virus problem if it relates to all of those things.
For the printer: try to unplug printer and go to the control panel and uninstall all printing drivers and devices then turn the computer off and plug the printer back in while it is off.Plug it back in and restart the computer and it should reinstall itself with Windows Plug n Play.
Internet: Is she using Mozilla or IE?
If all else fails, Run virus scanners and adware programs and try to rid of all of those. Make sure everything is updated too (Windows XP, printer drivers, network drivers, motherboard drivers, etc.)