.REG files are a common way of applying multiple settings to your Registry. Double-click it, the file is normally imported by the Windows Registry Editor, and once you've confirmed all is well it'll apply every single change with a click.

While this is certainly a fast way to update your Registry, it's also potentially dangerous, as you could be making hundreds of tweaks all at once without having any idea what they're doing.

RegMerge is a free tool which improves this process by displaying the contents of the REG file first, comparing it to your current settings, then allowing you to choose which, if any of the settings to apply.

Open any REG file and RegMerge displays a table listing the details of each setting: Hive, Key, Value Name, Value Type, and the value to be set.

A "Compare" column shows how each entry changes your existing settings, if it does so at all ("Missing" if your Registry doesn't have that setting at the moment, "Invert" if the setting seems to have been toggled, "Changed" if it's different in some other way, and so on).

You're able to choose the settings you'd like to apply. This can be done globally, for example asking RegMerge to apply "Missing" settings only, so creating new values without changing existing ones. Or you can just check individual boxes and clear others to suit your needs.

When you're done, clicking "Merge" makes your chosen changes to the Registry.

PLEASE NOTE: this is an alpha build, for testing only. If there are any bugs then it could seriously damage your PC, so don't even think of using it anywhere that isn't fully backed up.