Why is my computer not letting me see linked videos?

I share a computer where each person signs in under their own name with their own password. When I'm signed in under my name, sites such as thedailywhat, cuteoverload, etc. show a blank white box where a linked video should be. Other people on this computer aren't having this problem when they sign in. Also, everything on my screen shows up really tiny compared to others'. Any advice on how to fix this?