But even if there's no backup, sometimes it's possible to recover file which updated/modified. I would recommend you to make raw copy of your drive (with tool such as HDD Raw Copy[1]), so later you could use recovery tools (such as PhotoRec[2] or Recuva[3]) without worry the data overwritten since you keep using it.
I'm not sure how Windows stores text files, but if it's really just stored as plain text, it would be quite easy to do a raw search for some of the known words on the entire disk.
Brute force 4 missing Electrum words isn't cheap
~
2048^4 is rather large combination
According to
Ian Coleman ("BIP39 Split Mnemonic"), it takes 109 seconds to hack if you know 8 out of 12 words. I can't really believe those numbers, that would mean checking 161 billion combinations per second. But I am now curious how much processing power
some of the professionals have for this.