Installed Lubuntu-Desktop after constant crashes

I hate to say it, but after the update to Ubuntu 12.04 LTS I have constant crashes. The desktop "resets" and go back to the login screen. I lost some data because of that.

Installed Lubuntu, another Desktop Environment, and hoping that it doesn't crash again.
Lubuntu is a light-weight UI. Very basic. That doesn't matter, as 90% of my usage is in the browser. Cloud computing is cool. You just don't need to care what OS...unless it works.