Regedit is correct. Also you can edit things in the registry but you better know what you are doing otherwise you can make your computer inoperable. You can add / delete and change values within the registry if needed.
A lot of times virus's will change values or add things to the registry that need to be removed in order for windows to work properly (which is the reason why some virus's won't allow things to open or will not allow you to start or run particular programs).