Unless she has a bunch of programs installed and running like BigD mentioned, see if she can check with AT&T about a replacement. I only installed Google Maps and Opera Mini 5 (which she should use as her browser - it's by far the best for TP2) and I ran into issues with screen freeze and constant rebooting needed. Sprint was great and replaced mine and all is good now.
...at least until October when I'll upgrade to something as capable as a TP2 and inherently more stable than WinMo. When I find that something, I'll let you know 'cause it's not obvious to me yet.