Would be interested in knowing if SetACL Studio will work for this. It has a 30 day trial that ought to give you enough time to try it.
Probably not, as it's not a permission/security problem, although I have not tested this particular tool. Generally, when tools try to delete my test file they complain that there (supposedly) is no such file. Thanks for your suggestion, though.
However, I do
have tested a bunch of deletion/renaming tools suggested on the internet. None
Most problems with "illegal" characters are related to exceeding the Windows file/path name length limits or funny symbols from Unicode file names (and missing fonts). As stated above, the chkdsk trick doesn't work for me. I have even tried to delete the whole containing folder, but no luck.
The only option seems to be the special tool DelinvFile, but I think $31.95 (USD) is a bit much...
Anyway, in the meantime I have reinstalled Linux (not just because of this problem, btw), so I will remove the files in question bit by bit.
Concluding I would like to say thanks to you all for your kind help. Feel free to suggest more solutions, maybe they can help other users with the same problem, although I personally will use Linux to remove all problematic files left. Thanks again.