It's happened on move 35 to several of us. Customer Service says they are working on it and should have it fixed soon.
computer starts thinking
I hadn't noticed if it was move 35. It's happened twice to me and I thought I had a good position. Haha. It was just a bug.
Customer service replied that they were working on the bug. I wonder if they will tell us that it has been fixed. Somehow I don't think so.

We've just added a fix for the 'against the computer' issues members have been experiencing.
Can you go into computer chess, look on the bottom right corner of your monitor. Can you click on the java icon then Open Control Panel.
Once this is open, use the bottom box where it says 'Settings' - when that new box opens, click where it says 'delete files'.
Then OK
Once you've done this, refresh the page.
Sometimes the java icon is turned off from appearing in the tray. If you're running windows....
start button/control panel/java/advanced/miscellaneous/check box "Place icon in system tray"
Also try clearing your cache, and even your java cache. see: http://www.java.com/en/download/help/plugin_cache.xml
Then try 'against the computer' for me. If you're still having issues on there can you please let me know in detail whats happening.
Thanks
Twice now I have been playing against the computer and it's gone
into thinking mode for longer than I care to wait (several minutes).
Is this a bug or just a way for the computer to stay undefeated? How
long will it think?