Quote from: Plasterman on Today at 10:29:45 PM

Yes i have the old install on the external HD, also the walet.dat file is in there, i have a copy of the old wallet.dat file on 3 USB pens as well all encrypted.

If you still have an old backup copy just make a new copy(for safety) and make sure not to touch the original only use the wallet .dat copy and move it to your Bitcoin core wallet folder.

After that, you can reopen the Bitcoin core and change the password but before you change the password try to input the password into notepad first to check if the password is correct then copy and paste it to the Bitcoin core.

Be sure to remember the password because I had previous experience that I thought I had my password in mind but I forgot I added a few characters from my password.
So maybe you forgot that you added some characters at the end in your password?