WilliamG, did you try the registry change?? That should fix this problem.
When he says a "short time" he means as fast as the video card possibly can, not like turning off the screen after a minute or two. There is a slight delay, and if you flip open your screen very fast you might see it flash on, but it's not like you have to wait or anything. It turns off when you close the lid, and turns back on when you open the lid, thus the name "LidBehavior". Do the registry change before posting again.
(edit) I also wanted to mention, I am not using any modded infs, just the ones which came with my driver, which is the one supplied by Dell - version 220.127.116.11 according to the Device Manager properties. It works fine, runs all my games at highest (or very near highest) settings and 1920x1200, so like my custom title says - "Don't Fix What's Not Broken"! I suppose when something comes out that doesn't run fast enough for me, I might try modded INFs or unofficial drivers, but it is certainly not broken, in fact I had been using an ATI Radeon 9600SE (about 2 years old) before I got this laptop so it is a HUGE step up and I'm happy with it. (/edit)
sergiop, do you have the NVIDIA Geforce Go 7900GS card, or another NVIDIA card? If not, of course you won't find it because it is an NVIDIA thing! But if you do have such a card, then try installing a different (newer) driver.