If you go out and buy a brand new harddisk and plug it into your SKy+ box it is likely that it will refuse to start up, i.e. never get a green light on the front.
To format the harddisk you need to
1. Unplug power
2. Hold down the right and left key (on each side of the “select” key) while :
3. Plug in the power cord
4. Wait until the “ring” starts flashing, let go of the 2 keys
5. Press select (The green power light should now come on)
6. The “ring” should start spinning, wait until it stops spinning
7 Wait 2 minutes for the box to restart itself, press the power button
And hopefully the box should now start up correctly.