Applications usually scatter their configuration settings all over the Windows registry when they are installed, but in general there are two places you can find these settings in case you want to modify them or troubleshoot something. Specifically, per-user application settings are usually found in the following key or something like it:
HKCU\Software\Company\Program\Version\
and per-computer application settings are generally found at:
HKLM\Software\Company\Program\Version\