This is very handy for those users who did not receive an installation disc with their computer. It is not illegal, there is no product key involved and you will still need to use the product key from your original installation for any activation. Simply download the ISO which matches your version of Windows 7 and burn to disc.
An installation disc will provide users with the option to perform a ‘Repair Installation’ which would not be available otherwise. Plus, the inclusion of SP1 will save having to download and install loads of additional updates after a clean install, and negate the necessity to slipstream.
All versions of Windows 7 are available in both 32-bit and 64-bit editions. Make sure to download the version (Home Premium, Pro, Ultimate) which matches your original installation. All Windows 7 licenses support both 32-bit and 64-bit so that choice is yours.