How do you change screen resolution win 7 to default blindly without monitor?

To change the screen resolution to default settings in Windows 7 without a monitor, you can use keyboard shortcuts. First, press the Windows key + R to open the Run dialog, then type desk.cpl and hit Enter to open the Display settings. Use the Tab key to navigate and the arrow keys to select the "Resolution" dropdown menu; then, press Enter. Finally, use the arrow keys to choose the default resolution and press Enter again to apply the changes, followed by the Enter key to confirm any prompts.