HELP...I've done something terribly wrong!

I have been trying to clean up my computer. Several weeks ago I put some stuff in my recycle bin and finally deleted some of them today. I then dowloaded the latest Adobe Flash Player version and now I can't see any videos, just the box in the corner with the three geometric shapes. I am close to completely computer illiterate, so please help me fix this. I don't think anything I deleted is related to this problem because I left the stuff in the recycle bin long enough to see if any of it was necessary. HELP ME - No videos until this is fixed! I will be very appreciative.