Step 1. Start firefox
Step 2. Go to Tools
Step 3. There go to Add-ons
Step 4. In Add-ons press Get Add-ons
Step 5. Search for "cookie"
Step 6. Install the one named "Edit Cookies" and restart firefox
Step 7. Then go to filehost site you want to login as premium
Step 8. Login with non premium account. For example on megaupload you can use this Username: kenedaa Password: siavonen
Step 9. Go to tools again and select "Edit cookie" from bottom
Step 10. When you open it there is empty box put in there "megaupload" then press Filter/refresh button
Step 11. In there you should see cookie named "user" click on it and then click on button "edit"
Step 12. Then there should pop-up "add/edit cookie" window. Fill in there the content you have been given
Step 13. Then just Press "save". Close cookie editor
Step 14. Refresh the site and there it is premium account ^^