If it's just a matter of searching it without changing anything (no Search & Replace), export the whole registry to a .reg file and use your favorite text editor that supports regular expressions (Notepad++, Textpad, PSPad, ...).

To export the whole registry, right-click the Computer node in Registry Editor and select Export.

Watch out, the exported file can be huge. I just tried and the file was 250 MB big.

If it's just a matter of searching it without changing anything (no Search & Replace), export the whole registry to a .reg file and use your favorite text editor that supports regular expressions (Notepad++, Textpad, PSPad, ...).

To export the whole registry, right-click the Computer node in Registry Editor and select Export.

Watch out, the exported file can be huge. I just tried and the file was 250 MB big.

Encoding update: On WinXP, cygwin's file utility reports the exported data as Unicode text, UTF-16, little-endian.