Where is this website that you are trying to go to to play solitaire Or is this the solitaire that is built into windows (start, Al Programs, Games, Solitaire)

it is the one built into Windows

That shouldn't be affected by firefox 12, Firefox doesn't touch any Windows components related to games.

You can try restarting Windows, running all windows updates, but other than that I'm not sure. Can you describe step by step what the problem is?

All I can tell you is this. I got a new HP computer (64 bit). Previously I had a Dell Inspiron (64 bit). Setting up the new computer I downloaded the Firefox 12. It seemed to slow everything down and the cards wouldn't move in solitaire. I tried many things and shut down many, many times. Looking through Firefox's help I see that there are problems with the version 12. I installed it and uninstalled it several times. I found that as soon as I uninstalled it solitaire then worked. I hate Internet Explorer but it seems that I am stuck with it until Firefox resolves its problems.

Run all Windows Updates, install all needed service packs, etc.

Update your graphics driver (Firefox uses your graphics card for some rendering, and an out of date graphics card driver can cause problems. https://support.mozilla.org/en-US/kb/how-do-i-upgrade-my-graphics-drivers.

Update all your plugins (Flash, Java, etc.): http://www.mozilla.org/plugincheck/.

Download and Install MalwareBytes Anti-Malware, run a full Scan. http://www.malwarebytes.org/. This helps check that there are no viruses on your computer causing issues. You can uninstall this program after you clean off any infections.

Thank you. Did all that and it worked!