They might. What do you mean by locking up by the way? Just sitting there? Or when you're trying to do your normal stuff and randomly the system stops responding and never comes back?
Another thing to do is to enter a virtual console by hitting CTRL-ALT-F1, or that combo involving any of F1 through F6. CTRL-ALT-F7 will return you to X. But from there you can do some diagnosis and see if something is hogging the process.