Do you see this screen?
If you do, the problem is JSecure. Have you really forgotten your secret code? If so, read on …
Login to Your Hosting Account
Or you could go via FTP. Essentially you just need a way to get to your files.
Find Your File Manager
Every hosting company should give you access to your files, although the access may be in different places with each host. This is an example from the popular CPanel software.
Browse to /Plugins/System/
You need to access the /plugins/ folder than then the /system/ folder.