I installed a new hard drive and now when I turn on my computer the desktop screen size is like 3/4 of the screen. I need help fixing it to its normal screen size

No one gives a shit what trite garbage you write here.

I'm assuming this is a Windows machine. Right-click on your desktop. If you're on Windows 7, choose "Screen Resolution" and you can change the settings from there. For an older version of Windows, choose "Properties". On the new screen, choose the last tab labeled "Settings", and you can change the settings from there.

If your desired screen resolution is not available, then you'll need to download the latest drivers for your graphics card. The instructions for that would vary depending on what card you have, but the normal way to do it would be to go to the vendor's site and download the driver from there.

A just ruler amongst tyrants