Divided Registry In 64-bit Windows

Ever tried to run an old program under a 64-bit OS and found that it just wont work, even when you try every possible compatibility mode setting and running as Administrator?  Many people don’t realise that there are some key differences that can often prevent a program from working.

Both Program Files and the registry are split into 32/64 bit variants, in case there are 2 versions of the same program that need to be installed.  This recently caused an issue for me where i had to manually apply a registry patch to get the game to ‘work’ – under Windows XP it worked fine but would not work under Windows 7 64-bit.  The reason was because by default, the registry patch gets applied to the 64-bit registry, however the game was looking in the 32-bit registry.  The easiest way to solve this is to use the 32-bit version of regedit to apply the registry patch.  You can start it by running:

%systemroot%\syswow64\regedit

Then open and apply the registry patch.  See here for more information