Since Microsoft has removed official download links from their main site for general consumers, you have a few reliable options: 1. The Internet Archive (Wayback Machine)
The Internet Archive hosts many "ISO" files (disk images) uploaded by the community. You can often find original, untouched retail or OEM copies of the Windows 7 Home Premium 64-bit ISO here.
64-bit supports more than 4GB of RAM (Home Premium supports up to 16GB).
Windows 7 Home Premium 64-Bit: How to Safely Download and Install
If you are downloading Windows 7 Home Premium, the version is almost always the better choice over the 32-bit (x86) version.