crashing constantly

I have a bunch of mods, there is no doubt about that. I fully understand that a mod that i tried now makes gmod crash. Since i have not installed it ( whenever it crashes, it will not pick up from before, it will re-install everything), I cannot delete it, nor do I know how to keep said files from being downloaded and installed, is there a way to keep the mod from being installed and crashing my gmod? I can only get 5 minutes in at a time before the mod gets downloaded and shuts gmod down.