True but playing around in the program files directory can also cause program corruption and ULTIMATELY MAY
make a virus I don't know but it's possible. I have seen it happen before. But if you don't want a program just uninstall it simple. Why are you playing around in there anyway is another good question.
As for the access denied you need to change the ownership of the item to you by right clicking: Properties-Security-Edit (OR Advanced if you want to change other settings while your here) add your user name by pressing add and then apply and close the window. Change your user settings to full control and you will not have Access Denied no more