Help! I'm in trouble :(

I am currently running a lap top with Windows vista. I just now saw a folder in the start menu that I never have seen before. And it was 0 bytes in size. So I went to delete it. What happened was, it deleted EVERYTHING in all programs. Everything is gone such as disk defrag, disk cleanup, system restore, calculator. I tried searching for them to see if they were still on my computer and they were not. So whats the easiest way to get them back? I dont know what to do. Thanks in advance.

 

System restore was deleted as well. So I guess I need to back up my files, and reboot the hard drive/operating system? How might I go by doing that? I bought the computer at Staples, and it did not come an operating system disk.