AE not working with Leopard and fed up

Question

It happened a while ago, and set it up again, and again, again.
It all stated after upgrading to Leopard
Today I was about to listen to some music through AE, and once again it didn't work. I had the green light on, it shows as connected in my router setup page. I have change internet suppliers a couple of month ago and have brand new router, but it was happening with my previous router too. In fact in the last 5 months I have used 4 different router, all branded. Airport Utility couldn't find AE.
Today I spend more than 2h simply trying to set it up again.
It took 4 or 5 hard reset before Airport Utility finally found the AE.
When I clicked on continue, 9 time out of 10 I got
Base Station Error
Airport Utility was unable to find Apple wireless device
while it is was obliviously showing before
and back to hard reset.
If I connect an ethernet cable I get the self-addressed IP trouble, but strangely I have managed to set up AE only when the ethernet cable was connected, but the set-up was through WIFI, as it asked me to switch network.
I tried to switch off the firewall with no success either.
I looked at my local wireless networks using iStumber, and once again find some new network with the same channel as mine, so I changed mine to a channel not used. I did this a month ago already.
As I said some how after 2h of wasted time etc, I finally managed to get it going, and started to listen to some radio with Airfoil. After about an hour of listening, it when dead again.
Airport Utility doesn't find the device any more, like at the start of the day. iTunes doesn't make it available, my green light is on, my router shows it as connected, and of course I cannot print any more.
I am getting really fed up. It has been working ok for a couple of years with Tiger, but with Leopard it just works when either it wants.
After all these are Apple products, are not cheap, and don't work.
All are with last firmware, last upgrade etc..
Please tell me why all this is happening, why there isn't any fixes. We are 10.5.6 more than 18 month after launch of Leopard, with snow leopard about to become available. Is it because I am using a non intel machine?
Many thanks

Answer 1

Reading over your message, I am a little unclear about how far along you are in sharing your LightRoom setup with the Laptop. I am going to assume that right now Lightroom and the pictures are both on the PC and on an internal Hard Drive. And except for the scary message you had at the beginning of changing to ver 1.2, everything is working ok. Yes?
What I'd do is wait until you get the external drive up and working. Once you are satisfied that the system works ok, and you have tested it with whatever diagnostic software you use, you are ready to start moving your images to the new drive.
Do a good backup of your images to your backup drive.
Move them to the hard drive from within Lightroom: Use the '+' symbol in the heading of the Folders panel to tell LR to add a new folder from the external drive to the LR folders panel, and then drag and drop the folders already in LR over to their new home.
This way the LR Catalog will always know where the files are.
Then when you are sure that all the image files are on the external drive and LR sees them all and everything is working correctly, exit from LR and copy the catalog file over there.
I used to use windows systems, although I converted to Mac a few years ago. You should be able to double-click on that catalog file that is on the external drive and it should start Lightroom and you should be good to go.
I just used the word "should" three times meaning I'm not really positive about that last step; if I'm wrong I hope someone on a PC will post a correction.
Once it is working OK on the PC with the external drive Load LR on the Laptop.
Best Wishes!