This solution (desactivate/reactivate) will remove my plugin's settings :|

I have lots of plugins and I have made changes in the code. So I can't back up the plugins.

Ok Thanks Tammy :) I will try.

why cant you backup your plugins, just do a website backup from cpanel it backs up everything including your db. 

The only way to reset your website content, if I understood correctly the resetting is to restore your backup. Do you have one? 

No, I don't :/

You should probably go ahead and do one now just in case, it could save you big time. 

Do you know how to do a backup?

Do you use cpanel?

Yes, I know how to do a backup. 

Is it possible to empty some tables of my database to reset the content ? 

How will you know what to delete in those tables and what not? 

There's a lot of manual work needs to be done in order to achieve that, we can't provide you such kinds of instructions. 

Most of the content has the timestamp, which you can check of course via timestamp converter, but there will be a lot of leftovers, because there are corresponding records in other tables which are based on the ID of the data of the row you were going to delete and etc, so it will take a lot of time for us to explain that from scratch, we do not have time for that. 

Next time please do a backup. 

Thanks anyway

+1 ross  i totally agree its one thing to know how to do it, its quite another to explain it to someone else.  I have done it before using a combo of the original install sql and basically trial and error and finally did it... But i would hate to have to explain how to do that, its so time consuming just to do it in the first place.  

You are really better off thomas making backups all the time.  At least min 2x a month and then keep them for 60 days and drop them.  And dont leave a bunch of backups on your shared server, the host will have a fit.. Download them and you can keep them longer if you want. 

I will regularly make a backup. 

Thanks for your advice