Windows Explorer Stops Responding?

Ive been having computer issues lately (maybe a virus) so I reinstalled the OS and put Bitdefender Internet Security 2013 on as my AV (Norton last time). But the problem is that my Windows Explorer stops responding. For example: I go into my pictures and that loads fine but when I go to open a photo it loads and for a minute and finally comes up. That never used to happen before I reinstalled my OS. Im positive I did it right. Though when I try to close the window it says the Explorer has stopped responding.

Please help and thank you  
If there is any other info you need please let me know