I know it's an old question, but it's easy to check this out. Just create a folder with a bunch of dummy files whose names are each character on the keyboard. Of course, you can't really use \ | / : * ? " < > and leading and trailing blanks are a terrible idea.
If you do this, and it looks like no one did, you find that the Windows sort order for the FIRST character is 1. Special characters 2. Numbers 3. Letters
But for subsequent characters, it seems to be 1. Numbers 2. Special characters 3. Letters
Numbers are kind of weird, thanks to the "Improvements" made after the Y2K non-event. Special characters you would think would sort in ASCII order, but there are exceptions, notably the first two, apostrophe and dash, and the last two, plus and equals. Also, I have heard but not actually seen something about dashes being ignored. That is, in fact, NOT my experience.
So, ShxFee, I assume you meant the sort should be ascending, not descending, and the top-most (first) character in the sort order for the first character of the name is the apostrophe.
As NigelTouch said, special characters do not sort to ASCII, but my notes above specify exactly what does and does not sort in normal ASCII order. But he is certainly wrong about special characters always sorting first. As I noted above, that only appears to be true for the first character of the name.