Doom 3 won't start

Kind of a weird situation going on ... downloaded doom 3 demo few days ago to see how it would run on my system and it ran great on all high settings ... decided to go out and buy the actual game yesterday and when i went to install it it was already installed on my system (figured it might have been from the demo being installed but i had already uninstalled it) no big deal except it wouldn't start the game when i chose the play game option and wouldn't let me uninstall when i chose that option either ... bought my system used so maybe the previous owner had played doom 3 before on it but can't find any evidence of it on the hard drive so i'm kinda stuck ... any advice would be appreciated

 

You could not go into control panel and uninstall or do a system recovery to back you back to before you installed the demo? So it couldn't play at all? Was there an error message? Are there any other games loaded that you can test to see that if the install has caused the damaged or it's a hardware issue? What's your hardware? And did you update your drivers?

 

nothing in the control panel related d3 , all other games still play and run fine (cod4,bioshock,c&c3 etc.) no error message disc would start to spin like it was about to load and then just promptly stop with no activity on the task manager, and updated my drivers from laptopvideo2go about the time gears of war released and they have worked great for every game i've run, my hardware is hp dv6500t 2.0 ghz t7300 c2d, 2 gigs ram, 8400m gs, 200g hard drive ...