Win IE and Firefox use separate flash players.

See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

Thanks, but I had already done this.

Is this with one website, several?

Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies
  Warning ! ! This will log you out of sites you're logged in to.

Type about:preferences<Enter> in the address bar.

• Cookies; Select Privacy. Under History, select Firefox will Use Custom Settings. Press the button on the right side called Show Cookies. Use the search bar to look for the site. Note; There may be more than one entry. Remove All of them.
• Cache; Select Advanced > Network. Across from Cached Web Content, Press Clear Now.

If there is still a problem, Start Firefox in Safe Mode {web link} A small dialog should appear. Click Start In Safe Mode (not Refresh). While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe websites. Are there any problems?

Then restart.

This problem doesn't occur with any website, it is a game on a disc.

You're using Firefox to play a game on disk? What game is it? What format is it stored?

It is an older golf game by E A Sports, Tiger Woods PGA Tour '08. But so far as I know, I'm not using Firefox to play it, I'm using Windows 7. The game is installed from the disc, then played with the disc in the dvd drive. As a last resort, I wondered if there might be some interference by Explorer with Firefox after I installed Firefox, which might affect the game's performance. I say "as a last resort" because I've checked out or tried everything else I can think of, & clean up & defragment disc C regularly.

You said; which played fine on Explorer What do you mean by this?

Most of those type games do not use a browser to connect to the web. Those that do have there own internet comm sub program.

I think it best if you contact the games support site. This is not a browser issue I am thinking.

OK, thx. I only installed Firefox about a month ago, & was wondering if anything in Explorer might conflict with Firefox & cause any problem with the operation of my computer when I am not on the internet. Would I create any problem if I uninstalled Explorer?

mjollnir said

Would I create any problem if I uninstalled Explorer?

Yes. Win IE is part of Windows, and Microsoft uses IE to do its updating.

OK, THX.