HP have announced that it is canceling its much touted Windows 7 tablet PC to have been called the “Slate”.

The device was first unveiled by Microsoft CEO Steve Ballmer at CES 2010 in January and was supposed to hit the market in mid 2010. It’s now understood that HP is not satisfied with Windows 7 as a tablet operating system and has terminated the project (something CrunchGear mentioned months ago).

HP may also be abandoning Intel-based hardware for its slate lineup simply because it’s too power hungry. That would also rule out Windows 7 as an operating system.

So what will HP use as an operating system? Look for Google-powered devices, which have already been announced. And HP really does seem determined to make a go of the Palm WebOS. They said how important it was to them recently, and they will likely experiment with porting it to a slate-type device.