Personally, I would suggest you to use a download manager to download these files to ensure proper downloading of these huge files. Windows 7 Direct Download Links 64-bit Windows 7 Professional x64 ...

For most would-be Windows 7 users, a 64-bit version of Windows 7 is the right move. But if you don’t have sufficient RAM (at least 4GB), or you rely on devices that don’t have supporting 64 ...

Not sure if your installed version of Windows is 32-bit or 64-bit? One quick way to tell is by looking at information about your operating system installation in Control Panel.