Hi there, wondering if anybody out there can make head or tail of this situation that i've got myself into!

OK, so 18 months ago we had a PC that was connected via a standard modem/ethernet cable. I then went out and bought a MacBook and preceded to buy a router (myessentials ME1004-R) so that we could access the MacBook wirelessly. All went pretty smoothly, installed the software, connected the cables, set up the WPA etc and all worked fine.

Then last month the PC conked out which didn't bother me that much anyway as I had wanted an iMac for some time so we went out and bought one brand new direct from Apple.

Problem now is that I absolutely can't/have no idea how to get the wireless working again so that the MacBook can receive the wireless connection.

I took the 'myessentials' CD and popped it into the iMac, unplugged the router/modem leads as instructed and re-inserted them when prompted, chose a name, a WPA password etc but it always fails right at the final hurdle and never establishes a connection to the internet. The signal bar strength on the top right is full but when you click it, it say's "Airport: Not Configured".

The only way I can get online is via the ethernet cable - which is great for online browsing using the iMac but it means that nobody else can use the MacBook for online use as it can't pick up a wireless signal.

Despite the connection failing at the final hurdle when installing the router, I can still see it from the drop down list on the MacBook so it recognises but when you select it and open Safari, nothing happens and the blue bar gets maybe 20% of the way and literally stays there. Something on the iMac is preventing me from allowing this router to install and i'm flummoxed if I know the answer.......

So, any suggestions? A possible router fault or perhaps it's incompatible with the iMac (I doubt it)? Or maybe it's something a bit more technical that would need explained to me in the greatest layman's terms imaginable?!

I know the easy option would be to say that the router needs replaced but it's a classic situation of 'was working yesterday' and so it's a bit odd to think it's stopped working at exactly the same time i've bought an iMac. I suspect it still works fine but making it connect wirelessly isn't particularly as straightforward as you would imagine?!

Thanks in advance guys - any help would be enormously appreciated!