Today I logged in with Firefox 3 (as I do most every day), and I had a number of Tournament and Regular Game alerts. When I went to view the games, they didn't display properly; most disturbingly, the opponent's King is not on the board! After clicking to View each game, they also disappeared from the Alerts list (although that may be normal). You can see the highlights on the board, where the opponent's last move was made, but you don't see all of his pieces (although you do see some of his pieces, in some cases).

An example would be my current game against cuz.

Is this a system-wide problem? How do I clear this and get on with my games?

Thanks.

One time that happened to me when I was playing live chess, I couldnt see my opponent's bishops and I thought it would come back as I progressed with the game, but because of my overconfident optimism, I lost 2 games, but the next time I logged in, It was back to normal.

Try deleting all of the temporary internet files (sometimes called cache) that are stored by your browser. If you are unsure how to do this, here is a tutorial: http://support.chess.com/index.php?_m=troubleshooter&_a=steps&troubleshootercatid=1&parentid=0 . 

I cleared the Firefox cache (Tools | Clear Private Data...), and only the cache, and restarted Firefox. After that, I was able to see all of my opponents' pieces, and the web application seems to be function properly. Thanks for the tip, although this certainly has to be considered a bug in the Online Chess web application, and I'd appreciate it if you would report it as such.