Hi
I tried all the things you suggested but it is still not working.
There is an apple store in Belfast should I take it there?
Could this be a battery problem in the imac?
Hi sorry to pester you again
The mac went from the grey screen to standard start up, although this took 1/2 hour.
Once the blue progress bar reached the end I got a blue screen
Nothing else is happening, no icons I can see the pointer and that's all.
Edit: Oops. I just realized this post was 2 months old. I suspect you have moved on.
This sounds similar to a problem I was having this morning. It would be really useful if you could have a look at the system log (system.log) for any more clues. You can try to boot the machine into Single user mode to do this. I believe the key sequence during boot for this is to hold down the Command and S keys.
Once you find yourself at the "root" prompt, you should find the system.log at
/private/log/system.log
You can easily view the log without having to navigate from where you are with the following command:
cat /private/log/system.log | less
That vertical symbol before the "less" is the "pipe" symbol. You can see it on you backslash key.
Once the log comes up, you can navigate forward and backward through the log with the "F" and "B" keys. To exit, use the "Q" key.
The log can be confusing to read, but in my case I was able to see a section of errors that were repeating over and over.
In the end, for me, it turned out to be a permissions issue. Somehow, the root directory "/" had its permissions corrupted which made it so that one of the boot processes was unable to access a required file.
At this point I really don't want to give you a bunch of commands to try if you're not familiar with the system. I don't have enough information anyway. I'm just offering you another place to look for the problem. One thing that makes me think it's permissions related is that you said you can't reinstall the system. Neither could I, though I was attempting an archive and reinstall, not erase and reinstall. For the erase option, I wouldn't think permissions should come into play.