Hello, I’m Virginia a fellow Windows user.
Can you access the Microsoft account or is it just your PSN account which is the problem?
If you’ve forgotten your MS account details then you’ll either require the reset password option or account recovery.
Can’t sign in:
You can try also https://support.microsoft.com/home/contact & type Account Recovery in the box, then choose the Contact Support tab above & select Windows, then recovery from the drop down menus.
If none of the above work then you’ll require the account recovery form:
If it has been two years since you accessed the account then most likely it’ll have been deleted.
Unfortunately you’ll need access to your PS account in order to unlink the account. You could try contacting Sony/PS support to see if they can do anything.