1) Goto c:\inetpub\wwwroot\your_folder_name.
2) Go to properties of your_folder_name by right clicking on your folder.
3) Inside Properties, you will see a Security Tab.
4) Click on Security Tab and assign Full Control to EveryOne Role.
That's all!.... Now open your file again in browser and see that you have resolved the problem.
Note: I have write c:\inetpub because my windows directory is C Drive. If you have installed your windows in another Drive then write Drive\inetpub\wwwroot\your_folder_name.
Wish you all the best.