texture rendering problem with FS9

Hi,I have been experiencing a texture rendering problem lately in FS9.1 (but no problems w/FSX). I thought it was due to running FSACARS, but it's happening now on all flights. Textures, both aircraft and scenery, are failing to render properly, and everything is "greyed out" briefly while flying and changing views (2d-->3d cockpit/external/panning around/tower)...eventually they load, but it can take up to 20-25 seconds.By the time I reach my destination airport, FS9 is failing to render properly at all - everything is just "green nothingness" - no runways, taxiways, or buildings. This problem never used to happen, and the disc activity light stays on nearly all of the time while it's attempting to render anything/nearly everything....seems that the HDD isn't able to keep up the necessary speed to deliver the data fast enough....this system is about 18 months old.... I have FS9 on a 2nd internal 300 GB HDD, and my system is defragged by Diskeeper on a weekly basis, and it currently shows no fragmentation on drive E (FS9 drive), drive C (300GB boot and FSX drive), drive G (200 GB additional storage) or drive H (250GB external storage drive), so the system is optimized. All drives are single NTFS partitions.Here are my specs - Intel core 2 quad Q6600 @ 2.4 GHz4GB RAMnVidia GeForce 8500 GTWinXP Pro 32 bit, SP3 & all current updatesTwo Mitsubishi flat panel monitors running off the nVidia cardSoundblaster X-FI Extreme Audio cardI also have GoFlight's full airliner setup w/dual EFIS controls, and serial FP2 CDU.I've removed 3 empty slot's covers to aid in cooling, as well as setting the video card fan to 100% via Rivatuner - temp stays within a 3 degree margin when flying in FS9 (54 - 57 Centigrade), so temperature doesn't seem to be the problem....As mentioned, this is a rather recent development, and I'm not sure what to do about it, as FSX runs nicely (thanks to Nick N's setup guide!)Does anyone have any ideas on the problem and/or how to solve it?Thanks,Jim