Forum accounts do not get deleted.
If you want to never access you account again then do this-
1. Change recovery email.
2. Open Notepad and type some random letters like "aiueydvdbcbsj13".
3. Copy the letters that you wrote.
4. Go to account settings and change your password to random letters by pasting from what you copied.
5. Delete the notepad file.
6. Log out.
7. Switch Off Your computer.
That's it.