You are supposed to create your own recovery discs whilst your laptop is in full working order, using the HP/Compaq backup utility which is pre-installed at the factory. Ideally it should have been done when you first acquired it.
You can't download a Windows 7 recovery image from Microsoft because they don't accept OEM product keys. The OEM manufacturer is responsible for supporting your Windows installation, that's why they put backup software on the hard drive so you could make your own set of Windows recovery discs.
You'll have to buy a legit copy of Windows 7 which includes licence & Product Key, install it, then download the drivers for your particular laptop model from HP's website. Try Amazon for legit copies of Windows 7...