Folders open automatically.why?

hello.
my laptop Dell inspiron has a problem.it opens folders automatically before i open it manually.
the folders start to open recursively before i click on it with mouse or press enter key.
and the most important thing is that it's been just ten days since i formatted my laptop and got it back.this problem really annoys me.the antivirus also doesn't detect any virus in the system.i would like to know if it's a virus which is causing this problem.can you please help me to solve the problem?