When i put my clips in the timeline, this wierd green and black glitch appears on the clip and when i finish the project and render it, it still appears in the video and totally ruins it, i really need to solve this problem
Could you share your system specifications (CPU, GPU, RAM, OS version)? What's the exact version of After Effects you're using? Also, did you try the expert's suggestion? Did it help?
As suggested by @Mylenium this is something related to GPU acceleration. There is a ton of posts about this in the community. Check your Import Preferences and deactivate the hardware acceleration for video decoding, purge the cache and restart After Effects. This problem should disappear.