FSX won't load up after defragmentation

I bought the boxed FSX Deluxe Edition and when I start the program righ
after I install it everything runs fine until startup of a flight.
set the settings to max after I ran a system test on my comp saying
could with the 8G of ram, Intel Quad Core and the Nvidia GT220, but i
skipped so I figured it was because of FSX being 15Gb and alot o
fragmented files. So I ran the defrag and restarted my comp and cam
back to fly FSX and it wouldn't even start up. I have no idea why i
won't, I've tried doing it from startup, going into the disk itself an
running auto run and still nothing
Iv'e tried this three times and same results each time
Thanks in advanc
specs
Asus CG527
Intel Core2 Quad CPU Q8300 @ 2.50 Gh
RAM: Four 2048MB RAM each at 800 MH

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Blue4