I shut it down and removed the memory sticks and re: fitted them (gave the contacts a bit of a wipe though I couldn't see anything on them). While I had the beast apart I also gave it a bit of a "hose out" with the compressed air, and I decided to remove my CR-RW drive since it's been playing up and so I don't use it. I have a DVD-RW as well.
I put it all back together, covers on and the whole bit... I didn't get a chance the read the screen that it's been hanging at

... but... it wouldn't find my DVD-RW

.
After I pulled it apart again and rummaged around puzzled for a while, I found that the bus cable had disconnected from the motherboard as I fiddled with the memory cards.


It's not a very secure connection! But all is well and the world is a good and wholesome place again for the time being

.
Al.