Qwab,
I'm sorry to say, it's not DELL that's the culprit. If you want to point fingers, point at Microsoft. I know for a fact, that it's them causing the issue and not DELL. I have had many customers with different PPCs report this issue.
Here is something that might help you all:
http://www.scarybearsoftware.com/ppc...ar2003fix.html
Each time a WM2003 PPC resets it adds a 3 records into the notify queue, which are NOT needed. This is the culprit for some of WM2003 slow downs and it also causes issues with the alarms not firing. Please download their utility and give it a try. It's free. There are two different utils, a do it your self and an automatic one. Use the do it your self one so you can see what is going on and if it solves your issue then go back and download the automatic one.
Let me know if this solves your issue. I have a few other tricks you can try. I want to know what solves your issue as there are several issues that are similar going around and I'm trying to track them.
Thanks