Notebook blocks

[Martín Marqués]

I'm have, since I bought it, problems with by Dell Inspiron.
Basically, well I close the top (notebook is on) and I open it, the
notebook gets blocked, and I can't get it to work. I have to leave it
closed until it hibernates, and then when I open it it comes back to
life asking me for my password. AFAICR, it only happens when a user is
logged in, not with the KDM login screen.

Any ideas on why this is happening?