You must have a valid 25-character product key to activate the software during or after installation.
If you have the installer, ensure your system meets these minimum 64-bit requirements: You must have a valid 25-character product key
While official downloads have been discontinued, you can still install Office 2010 if you already own it through the following methods: You must have a valid 25-character product key
Some users rely on unofficial archives like Internet Archive to find ISO files for recovery purposes, though these are not official Microsoft sources. System Requirements for 64-Bit Version You must have a valid 25-character product key
Windows 7, Windows 8, or Windows Vista SP1 (64-bit versions). Processor: 500 MHz or faster. RAM: 256 MB minimum (512 MB recommended).