The safest method is utilizing your original retail installation disc or the official ISO file backup you saved when purchasing the software. You must use your genuine 25-character product key during the setup process. 2. Physical Backups
If you prefer a one-time setup without a subscription, consider these free, open-source alternatives that are compatible with modern file formats (.docx, .xlsx): microsoft office 2010 64 bit free
When Office 2010 was active, Microsoft offered a free 60-day trial. Today, Microsoft has removed those trial links. You cannot legally download the 64-bit installer from Microsoft.com without a valid product key. There is no "freeware" version of Office 2010. The safest method is utilizing your original retail