Unable to maximize windows parallels screen size

I just installed parallels but and when I launch it it gives me a window and the window is a fourth of my Mac's screen size. The window for my Parallels is small and I want to drag the corner of it to make it larger however, it will not allow me to.

 

Hi @KevinL10 , please try Actions > Reinstall Parallels Tools and check if that works.

 

Hey, Kevin, did you get that fixed?
I do coursework and research hplc detector and it is very important for me to use some Windows OS functionality. I have few programs that need Windows OS, but I can't resize the window. It is disappointing

 

From the screenshot, it seems Windows installation is not yet complete. Please complete the installation and check. If you face any issue, let us know for further assistance.

 

We request you to share the screenshot of your Desktop to check and assist you.