Thoughts that may help:
First, your search may be helped if you can specify a date range from just before it was created to the present day. Not sure what Windows parameters to use with a search to make sure hidden files are included in the files searched for. But the principle is to use file attributes besides the file name itself to aid in searching.
Second, I recall an old DOS command called ATTRIB I used to list all the hidden files on my machine (and change their file attributes to what I desired)...but that was back in the old MS DOS 3.3 days. Since I'm not a Windows expert, I don't know if this command or one like it is still available under modern Windows OS. But the principle of searching for only hidden files seems like it might lead to paydirt.
Third, recently at work I had to search my work PC (Win XP) for any *.md* named files -- and provide a listing to someone. Using the Windows XP GUI search function sucked because it didn't provide a way to save the listing of files found. Searching google I came up with the following way of doing a search on the command line in Win XP that results in the search results being saved to a text file. Modify the steps below for your own purposes. Hope this helps! Good luck!
The way I produced the search result listings for all the *.md* named files on my work PC's "c:" drive was as follows:
1) Click on START/Accessories/Command Prompt to open a DOS window;
2) On my machine, the DOS window opens at the "H:" drive (a network drive). Typing "c:" and hitting enter changes to the top most (i.e. root) directory on my desktop's "c:" drive;
3) Typing "dir *.md* /s/b>louis_mdx.txt" (without the quotes, of course) at the dos prompt and depressing enter performs a search and pipes the search results to a new text file.
The search is even quite fast, unlike the nice gui search with the "doggie....in the window...the one with the waggly tail..." ;-)