carwiz said:
Just about every "program" on your system uses the registry. Included in "programs" is various Windows 7 functions and features. Think of the registry as a storage for parameters that these programs use to control functions. Everything from where a window shows up on the screen to how a program will function on your specific machine. Changing or removing entries through Regedit bypasses the edit function of many of the programs themselves. The registry is where these programs store Preferences and Options that would be set through the program's menu and controls how the program will work--Or not work.

And, as already stated, changes may not show up right away. Or they may show up sooner than you think when the system won't boot or crashes when you try to run a program.
aaa I see now...