What button should the user press repeatedly during the primary boot to enter safe mode in the case that a technician is assisting a user in booting their PC into safe mode and the PC is running an older version of the Windows operating system?

When you start a Windows computer in Safe Mode or Safe Mode with Networking, it will only boot with the essential settings. Safe Mode starts the computer with just the drivers that are strictly essential. Safe Mode might help if you suspect driver problems or need to change system settings that are normally inaccessible because of booting issues. Press F8 repeatedly to enter Safe Mode during primary boot.