problems recognizing hardware

AB ContorolLogix 4 slot rack w/cpu
logix5561 cpu
Windows XP

So here's the deal. I had everything running fine on this rack (had a DeviceNet scanner, DC Input, and Analog Output all plugged in) and I was running some tests. I had problems with getting the DeviceNet to recognize a few devices, so I was working with getting that, and after one change (I don't know which one) the cpu refused to let linx (or anything else) recognize it. I restarted everything, and tried changing settings back to normal, but to no avail. I then removed all other cards from the rack except for the cpu, and tried to see if linx would recognize it then. Nothing. RS Linx sees that its in a different slot when I move the cpu around, but if I try to click on device properties, I get the 'unable to connect to the selected device error.'

Needless to say, I'm about at the end of my patience with this thing, especially after trying to fix one malfunctioning system and causing another to go down... (working on devicenet and crashing the cpu)

Help?

Let's check our basic tires and brakes.

Make sure the chassis is grounded, and that your serial cable or Ethernet cable is in good shape.

Check the controller and any communication modules for the 2007-era "Atmel64" issue. If you have a bad backplane chip it will drive you nuts looking for it.

Shut down RSLinx Classic and delete the Harmony.RSH and Harmony.HRC files, then reboot. That will make sure there isn't anything wrong with the drivers and their configuration.

If you are running a mix of RSLinx and RSNetworx revisions, consider going to a matched set, like RSLinx 2.54 and RSNetworx 9, or RSLinx 2.57 and RSNetworx 10.

I'm a DeviceNet expert and even so I sometimes run into systems where I can spend more time chasing around the components and links between those components than solving the actual problems. That's why I still keep a boot partition with good old XPSP2 and a 1784-PCD that always works.