S7-315 Lock-up

Help! We are doing our first Siemens S7 project. We are using a 315 CPU, and programming with Step 7 Ver. 5.2 software in Windows XP Professional.

We established communications between the programming laptop and the CPU and tested a small program successfully. Then we configured the analog I/O card to match the part number of the one ordered. Unfortunately, we failed to notice that the card shipped was the wrong part number, and didn't match.

Now the CPU is locked up, we cannot re-establish communictions with the laptop, and the software error message is "Online communication to the program adapter failed."

Power cycling and rebooting the laptop, power cycling the PLC, and reset using the keyswitch have not helped. At this point we are dead in the water, and our supplier's tech support guys are all out for training or otherwise unavailable.

Is there another way to reset the CPU, or any other suggested recovery techniques?

Update

Through persistance and creativity, my PLC expert Tim was able to get communications back to the PLC. This was done by donwloading an incorrect configuration to the communciatiosn adapter (6ES7972-0CA23-0XA0) and then downloading the correct configuration.

However, there is still a major problem. Tim can download and upload function blocks, but he cannot access or upload or download the OB1 file, which is apparently the main logic organization file.

Suggestions?

CPU stop. Open a project at blocks level, then PLC-->Clear/Reset

Thye CPU should do an over all reset by turning the key switch fully CCW and hold until the light blinks 2 times. Release and then switch CCW 1 more time. Then release.

Thanks guys - Tim has us back in control of the PLC. We did get the reset cycle to work, but we still had problems downloading the OB1 file. I'm not sure why, but he was finally able to download a simple one input turns on one output ladder, and then we were OK. We can now download our "real" application.