Windows 7: Adding passwords to certain folders?

So my pc gets used a lot by other people and i have files that i don't want them to go through and ive been wondering how can you put a password on a certain folder ? i used to hide folders but i found it annoying , so does anyone know how to do it or a certain program that will help me . e.g i click on a folder and it gives me a pop up asking for a password to proceed?

Thanks in advance i am using windows 7 ultimate

You can put a password on folders without some type of 3rd party software.

Thanks for the help guys but now i am looking for 2 things one to put a password on a partition and lock and even maybe hide from the software and no one can see it or go into it with out the password something like that.
2. maybe something like a virtual partition that takes gb out of a certain partition and makes it into virtual one and i can store data in it and then hide it when i want.

How it works?
Just install Secret Disk and choose a password. Then, start Secret Disk. Click unlock button, enter your password and you will see one more disk X: appears in My Computer area. You can now start working with your private files to save them to secret disk X. When you need protection just click icon in the tray area to lock secret disk and it will disappear within one second with all contents! When you want your files back, just open Secret Disk program, press Unlock button and enter your password. Its easy!

How would one go about doing this? I'm always trying to avoid using extra software . .