Mine also happens about an hour to an hour and a half into a flight

i have the same pc without any problems, although when i switch planes a lot or use the menu bar a bit too extensive, my FSX freezes, but since i also had this problem on my older pc, i say its an FSX bug. There are many topics about this and there is some on the internet with a solution to reduce this, google uiautomationcore.dll and you will find some of those.

don't worry about the brand dell.. some people have bad experience with some brands and one says dell is crap, others say its hp or apple or whatever brand they had problems with, but you cannot judge by it since you don't know how they used their pc.  I myself am an IT guy at a big worldwide company and we use Dell in the whole of Europe and hardly have any issues: servers, desktops, laptops, you name it.
Also, if Dell is that bad, why are they in the top worldwide selling brands.

I don't think it's just because it's a dell I don't have any problems with dell It just seems like something's not right. Tonight I ran into some heavy weather on fsx(on real world weather) it was like 200ft ceiling and 1/2 mile viability no precipt, and I took off turned towards my destination prob 4,000 ft and the comp just shut it down and showed an error message stating that the comp has run out of memory you need to restart fsx and lower the settings,graphics,scenery,etc. but the graphics aren't even on Max settings and I have no add-ons...that can't be right, can it? I mean it has 16gigs of ram, and my previous comp which was half the system this is never had to shut fsx down and tell me to lower the settings.

Thank you I'll check it out