when i start up Descent 3 i then have to go through the setup options and once i've completed that i go and click on play but i only get sent back through the options setup over n over again and are now unable to run the game...

What are your system specs?

to give you a ruff idea my system specs are....

Intel core i7-2600 CPU @ 3.40GHz
12.0 GB of RAM
Windows 7 witch is a 64-bit Operating System
and sommick like a GeForce GTX 520

but thats a ruff idea though.....
one time i used to be able to play descent 3 on this system but now i cant its possibly due to updated drivers
that the games disagree-ing with and i may have to re-down load an upto date version of D3/or patch the game up
some how

Try downgrading your video drivers. Newer ones may not always be the best.

this has nothing to do with drivers

right-click on the descent 3 shortcut on the desktop and tell Windows to start the game in adminstrator mode - then it works

this appears to be a quirk in Windows 7 and 8 (and Vista probably too) - they can be bit bossy at times

a thing that sometimes also helps is to remove write-protect status from a programme directory - e.g. should you have wondered why you have to change your setup/configuration stuff (e.g. keyboard layout every time you start a specific game) then this little trick solves the problem