Open up task manager and go to processes. You'll see java running in the background. Click on it and then press "End Process". Then try running minecraft again.
Having the same issue whenever I try playing Minecraft with 1.13.2. Works fine with 1.13.1 and all of the versions prior to 1.13.2 but 1.13.2 itself will not work. I use Windows 7, 32-bit version.
Open up task manager and go to processes. You'll see java running in the background. Click on it and then press "End Process". Then try running minecraft again.