Windows 7: My friend upgraded me to cracked Ultimate! HELP!

My friend upgraded my windows 7 home premium x 64 illegaly to a cracked version of windows 7 ultimate. I want to restore it back to home premium but it came preinstalled on my laptop so i dont have a product key to enter to re validate my windows. Please help!

If Home Premium came with your laptop, assuming you bought it from a legit retailer, you should have a sticker on it with your Home Premium key. If you don't see it, remove the battery.

If you have recovery disks, or a recovery partition on the HDD you will not require a key for activation, as this will be pre-activated. if no,t as stated above, you should have a re-activation key somewhere on the system or in the documentation.

If you have a dsektop computer, your product key is either on the side or at the back of your computer.

If you have a laptop computer, your product key is at the bottom of your laptop.

You can't miss it. It is very conspicuous.

There is no way to downgrade. You will need to do an install from your Windows Home Premium OEM media. They usually send these discs as "Repair Discs". Using such OEM media, you should not need to input any product key since Windows will look at your BIOS/EFI for the product key.

About an OEM Windows install media, even being the same version as what came with your computer, if is not an OEM, or if is an OEM from a different vendor as yours, it may ask for a valid product key. Get a media from your manufacturer and it should be activated automatically. There are other "ways" to fix that besides reinstall, but I believe this may be incorrectly tagged as "piracy" (tip: "slmgr.vbs -ilc your-manufacturer.xrm-ms") - although this is an official tool from Microsoft, it usually ends up being "misused".

Previous advices are also true: product keys are always labeled on each and every computer from any serious manufacturer. You should only use an OEM install media. Again, BIOS activation or OEM product keys will not work with a retail copy of Windows.