START with the 2.o upgrade script first.
In SQL MMS
select your database store>
Right Click>
Add NEW query >
Copy and paste the Update Script 2.0 ( then next version SCRIPT) ETC. from nop
Can't open it? Use notepad to open the file and just paste inside new query.
Then hit execute !!!!! the red icon
now repeat over and over each time until your up to 2.4.
THEN add your website back.
You are only updating the database.
does this help?