I downloaded Code Font and it looks normal at the first time. Then, I used it for PowerPoint Presentation, and it always turn to Arial. How can I fix this?

Thanks in advance!

In the new computer where you display the presentation the font must also be installed, otherwise the system changes the font to the default font, Arial in this case.

But this not happens in other font I've installed...

In that case, you failed to embed the Code font in your presentation. Try to understand what you are doing.