I'm running 32 bit Vista and I have an X-Fi.
Initially when I started up Overseer it crashed due to Data Execution Prevention, so I added Overseer to the exclusion list. I then started it up and I got a blank full screen, so I waited a few minutes, but nothing happened. I then tried to get back to the desktop by using Windows combinations like bringing up Task Manager and alt + cntrl + del but it didn't minimise, so after getting no response I pressed my power button to try get it to safely shut down, but still got no response so held down my power button.
I then tried disabling my X-Fi, as I saw a forum post mentioning crash problems once in the game, but then I just got the Data Execution Prevention problem again.
Its probably just Data Execution Prevention that's stopping this game from working, but I haven't seen anyone else post start up crash problems.

Could you post your system specs please? Also have you tryed running this in compatibilty modes, with administrator permission etc?

I have the same problem, but after ctrl+alt+del, a screen with options, new game etc..
appears. Nevertheless mouse don't move.
video card: ATI 4870x2
sound card: X-Fi fatality edition
CPU core quad 9650
MB Asus maximum extreme
Vista 32 bit ultimate

For starters make sure you have the game on the DEP exception list. Second I would disable one of your gpu cores using the ATI control panel. Make sure to run the game with administrator access and then set the game to run on core0 of your quadcore. You can also try some of the compatibility settings. Lastly disabling the sound card and using your motherboards sound seemed to stop the crashes for other people.
Thats alot of stuff to try but older games tend to hate dual and quad setups.

Installation defaults to Windows 95 Compatibility Mode and run as Administrator. I haven't tried any other settings.
Video card: 2 x Geforce 8800 GT
Sound card: X-Fi
CPU: Core 2 Quad 2.4 GHz
Motherboard: Nvidia 650i
Vista Home Premium 32 bit
After seeing your recommendation, I also tried turning off SLI, which didn't work. I'll try to enable the on board sound card and then disable the X-Fi again.

you could try changing lock video -1 to just 1 in tex ini file, this settings does help with mouse problems.

I am having the same problem, but running on a completely different HW and SW (Win XP, Geforce 8500, AC97 audio) with DAE turned off. Unfortunately, Overseer doesn't log anything with Event Log, so I am at a loss as to what it doesn't like :-(