Maybe, but 'freezing' is really difficult to diagnose. It may be overheating, it could be a module conflict with the new drivers, or it could be a bug in openoffice.org and nvidia drivers. First places to check would be /var/log/messages or open up a terminal and type dmesg. The problem is that you would need to do that before the freeze. Here's an idea:
If you can reproduce following your steps above, then, open up a terminal and top top. Then, watch the output for excessive CPU or RAM usage. If you begin to see it spike, in another terminal type dmesg to see if anything is reporting problems. You could also watch /var/log/messages as it's updated by opening up yet another terminal and typing:
tail -f /var/log/messages
You may have to be root to read /var/log/messages.