Actually, you need 2GB of "available" memory. But if you've got 15Gb of RAM installed now, this should not be an issue.
What version of Windows are you on? I'm on Windows 10 version 20H2 myself.
From an administrative command prompt try an online system cleanup. The command is:
DISM /Online /Cleanup-Image /RestoreHealth
Reboot when done. Note the process can take 10 minutes or more.
