Internal HDD screwed - HELP!!

Hi, not sure what happened but I was watching a movie on my ATV, the apple logo appeared on the screen but now nothing! The HDD is not found. I have a windows PC and have tried a few manufacturer diag tools but no luck. I have a new HDD of the same size and type but my problem is how to I get ATV back to factory settings? I have had a trawl around and found a few places but do not understand what I should be doing. If someone could give me step by step instructions I would apreciate it Cheers

You can reset the AppleTV through the Settings --> General --> Reset Settings menu, select the Factory Restore option.

If you need to setup a replacement internal drive, a step-by-step guide for doing so can be found here.

Thanks I will have a look