Out of Memory Error

Hi guys, for the last few days I have begun to experience problems in FSX during landing. Especially when I use the Thomas Ruth a340 series. Yesterday while coming into O'Hare, my gauges freezed up in the virtual cockpit. When I tried to switch over to the 2d panel, the screen turned completely black. So I went back to the virtual cockpit still with no working gauges. When I minimized FSX, the gauges would "refresh" meaning that the quick second I maximized the FSX window my gauges updated the speed, altitude, etc but frozed again.So I had to land gaugeless and I couldn't reverse the throttle either so I had to shut the engines down upon landing which was a big mess. Today, I did another landing using a KLM POSKY 777 in Beijing and while on final, I had an out of memory error and FSX closed immediately. I didn't think anything of it till just now when I was doing another approach using the Thomas Ruth A340 again while landing in Zurich. My gauges frozed during final approach and then while I tried to manually land, I recieved another out of memory warning with the usual APPCRASH and Terrain.dll was to blame. This is very strange to me because I have never had any memory problems with FSX on my computer and I should have well more than enough of memory. Here are my specs:Intel Core 2 Quad 2.5GHZWindows Vista 64Bit8gb Ram1tb Hard DriveNvidia GeForce GT 230 1.5GB