Screen resolution trouble in LMDE

[Gryphus One]

Hi.
A few days ago I started using LMDE 201109 Gnome 32 bits and in general it's fine, but I have a problem with the resolution of my screen:
I'm using a laptop with a 15.4" screen and a resolution of 1280 x 800. However, most times I boot, the operating system sets the resolution at only 1024 x 768. You can even notice that the proportions aren't even the same, so you see things horizontally stretched, much like when you have just installed Windows XP and haven't installed the graphic drivers yet. And when this happens, if then I go to the resolution preferences in the Mint menu, I can't select a higher resolution. But the weirdest thing about this issue is that it only happens SOMETIMES, whereas other times it boots with a good resolution. Also, when I get the correct resolution and I'm just doing a normal use of the operating system, sometimes the screen turns black for a very short instant and then I get it back (it's like a black flash), something that I don't remember happening when it boots with the bad resolution. My graphic card (I repeat that it's a laptop) is an Ati Mobility Radeon X1600 (it's a 5 years old computer).
Any ideas?
Thanks.

[proxima_centauri]

* Moved to LMDE Newbie Questions forum

[Gryphus One]

I have just found out that there's no xorg.conf file in /etc/X11. Might that have something to do? should I create that file?

[xenopeek]

You may want to try this: http://forums.linuxmint.com/viewtopic.p ... 85#p444558

[Gryphus One]

You may want to try this: http://forums.linuxmint.com/viewtopic.p ... 85#p444558

Well, I haven't done that because I just haven't had this problem again, even though I didn't have any software updates until yesterday. It's just unbelievable how random this problem is. Now I'm having other two different problems but I will create other threads about them.

But please don't lock this topic yet because I don't think problems get fixed by themselves, so who knows if these days I'm just being lucky and might get this problem again.