We're running Ubuntu 11.04 on quite a few Dell machines, but I am noticing that on some of them (including mine) Ubuntu freezes on randomly.
Normally when the screen goes to lock mode and you press a key to wake it up, this will happen.
Only mouse cursor can be moved but nothing else can even be clicked.
The only way out is to either go to terminal with CTRL + ALT + F1 key and re-login, or do a hard shut down.
Has anyone else also seen this happening?
What's the cause and solution/prevention!?