Hello Captain Sim forums,
I have the same issue as Steven. I have a store bought FSX and X Pack (not gold Edition). I have installed it 4-5 times over the past years. I just attempted to reinstall FSX last night to repair a bogus add-on that had no uninstaller. I tried the same things as Steven; installer flashes then dissappears. Once or twice a dialog popped up asking if this program has installed correctly. It did not of coarse sense the installer ran for 1/100 of a second. I moved the DVD files to HDD and tried to run from there but no joy.
I have tried disabling my Anti Virus, taking ownership of setup.exe, setting security to full control of setup.exe and adding setup.exe to the Windows Firewall exceptions list. Still no joy.

:-/

I searched for an answer and finally found this topic.

Win 7 Pro
i7 960 OC'd @ 4.2 GHz
12 GB 1600 Kingston HyperX ram
256 GB Samsung 840 Pro
250 GB x2 HDD Raid0 (FSX drive)
EVGA GTX 680 FTW+