(Rufus or Windows USB/DVD tool).

Changing Windown 7 Professional from 32-bit to 64-bit - Microsoft Q&A

Select the partition where your current 32-bit Windows 7 is installed (typically Drive 0 Partition 2).

Instead of downloading the file individually, system file corruption should always be fixed using official Microsoft utilities like the System File Checker ( sfc /scannow ) via the Command Prompt. The Reality of Upgrading 32-bit to 64-bit