G5 and MacPro hard drive swap and display problem

Hi Folks,
Hoping someone can help me figure this out. I swapped HDDs between a G5 and MacPro this morning. The MacPro was connected to a large LCD TV via HDMI for it's display (using a DVI to HDMI adapter) and it worked great for just scrolling images of our projects (no audio). When I put it's HDD in the G5 and connected it to the display the same way, I got nothing on the screen. Thinking it was a video card issue on the G5 end, I plugged in a different monitor and rebooted the G5. This time I got the flashing question mark folder meaning it couldn't find an OS to boot. So now I can't tell what the issue is. I thought HDDs between G5s and MacPros were the same? If not does this mean the older G5 drive won't work in the MacPro tower? (I haven't tried yet). Thanks in advance!

 

Hi Guys, thanks for replying so quickly.
The MacPro disk doesn't have anything on it, could I just toast it and reinstall the OS? Will that fix the partition table problem and allow it to work in the G5?
How would I clone the G5 disk (the one that has all the data I want to save) so it would work in the Pro?
I tried using MIgration Assistant with firewire between the two but no go...
thanks again

 

ok, seems pretty straightforward. Then I should be able to erase the old G5 disk and reload OS X on it with the GUID setting

 

any issue with the video card in the G5 driving the LCD display with DVI to HDMI adapter? Earlier research seemed to indicate no issue

 

I'm ok with no audio in this case. Just wanted to make sure before I toasted the old G5 disk after cloning it to the MacPro disk.
Thanks!

 

sorry, I should have clarified: I am swapping the G5 I use at home with a spare MacPro here at work, but need all the data from the old G5. I tried Migration Assistant but it didn't work so now I'm restoring the G5 disk onto the newly erased MacPro disk like you said. It's chugging along nicely.
I just realized that I don't have to do anything to the old G5 disk if the restore goes ok; i'll just pop it back into the G5 that's now here at work and create a new user account to run the slide show.
Sorry for the confusion!

 

so far, so good

well, after putting both the G5 drive and the MacPro drives into the spare bays on my work MacPro, I erased the MacPro drive and restored the G5 drive on to it. I am happy to be writing this from home using the restored drive so all seems to be good for now. Tomorrow I'm popping in a 500GB drive in here for TimeMachine.
Thanks for all your help everyone!