I hope you're all sat down with a good cuppa for this tale of Bad Apples
I was working on a friends out of warranty iMac 27"
They were having an issue where the Mac screen would go off but the Mac still running in the background (like a screensaver) and it takes a sequence of presses to get it back displaying. But the screen was brighter on one side than the other.
Things went kind of bad to worse with a PSU blowing then the screen connector getting damaged (long headache of a story)
As the screen needed replacing anyway my mate bought a second hand iMac 27" same year but slightly beefier spec (his orig was core i3 and the newer one is Core i7) and swapped the Hard Disks over
Now everything sort of works (no screen issues anymore) with a few minor niggles
1 - Upon swapping the HD's over Windows Activation popped up but seemed to re-activate fine. But a week later Windows Activation popped up again. It's running Windows 7 as it was set up when the Mac was purchased from PC World when new and unfortunately no CoA present. Would PC World supply a CoA?
2 - The Apple wireless mouse no longer works in Windows 7
That seems to be about it
So what I need to know is Windows Activation - If it asks for re-activation can Windows be re-installed the same way as on a PC (with a valid CoA) and without losing data
Plus the Wireless mouse would setting it all up in MacOS make sure it works in Windows?