When you open roblox a notepad file comes up and says some text and the roblox window is all blank Why does this happen

It sounds like you somehow have Roblox files associate with windows notepad instead of the Roblox Studio. Right click on the place file you want to open, select "Open With" and click "Choose program...". Then, select Roblox Studio from the list, check "Always use the selected program to open this kind of file" and hit okay. That should fix the problem.