WP2: after moving server some old posts aren’t justified

I moved my blog to another server, to use a domain I acquired. After moving everything and restoring the backup of the MySQL database I made of the other server on the new one, I realized that some old posts – the first posts of the blog – appear with a wring paragph formating: everything is aligned on the right, including the header of the post with the title and date of the post. they should be justified as the most part of them are. I looked their content on the “Manage” tab of post on WordPress management interface, but nothing is wrong, there is no redundant code, at least it is not visbible (the rich text editor is turned off, so the all the codes are visible to me).

I deleted on of them and reposted it with the original post date and it became justified as it should be. the problem is that I don’t want to deleted and repost all of the problematic ones because there are comments in it.

Besides, if you navigate through the “next” link you’ll see the post with paragraph problems, but if you click on the link of the post it appears perfeclyt formatted on a page alone. The most part of the problematic post also appear correctly if you nevigate using categories or archive links, though some still don’t. So, is it a problem with any of the PHP files? Coulld it be any of the PHP files on WordPress root folder or would it be on the theme folder?

Can someone help me, please?