Flickering in Facebook Games - Suspect Graphics Card

My partner likes to play that Candy Crush game on Facebook, but she's finding that the buttons on the game flicker annoyingly all the time. I had a look and I figured it was a graphics card issue, so I updated the graphics drivers. That didn't work, so I updated Adobe Flash. Still no joy. All other graphics oriented stuff works fine, only the game in Facebook is affected.

Her specs are as follows:

GPU: Radeon HD 7770
CPU: Phenom II 955
RAM: 8 GB
Browser: Firefox
Windows 10 Home Edition

If anyone has any ideas on how to solve this, I would appreciate hearing from you very much.

Thank you.

Which browser is she using to play the games? Have you cleaned all browser settings?

Turns out that it only happens when she uses Edge. Firefox doesn't have the issue.

I've advised her to use Firefox in the future.

Marking this one as solved.