Every time I open up Gmod, steam displays the common, "Preparing to launch" message, and right before closing, it shows a hollow window very briefly and Garrys mod on the taskbar. The game never starts. I'm having close to the same problem with my source game,:TF2.
I know for a fact this laptop has had an unstable background, and I recently had to install XP and then Vista to get it up and running again. It's not mine personally, I would never take such terrible care of my comp back home. I've tried so many things to no avail, including launch commands.
More aboutpreparing launch garrys starts
All fixed, forgot to do the obvious. (update my drivers)