Friends are you see links from his site? :
Look at the part of the link highlighted in red color and you can tell me how to create redirect?

Pretty much have 2 options. Install dbseo and it'll take care of it for you if you set up the link structure the same way... or do what Brandon posted. Good luck!

Or a third.. paid option.. dbseo offers full support to do this if you buy it.

I went with option one when I switched with no ill effects. Everything redirected to the right urls with no problems.

If you do not redirect those old urls to the new ones any sites that have links to those urls will instead be linked to broken pages.

Also, google will have to reindex all of your new urls if not redirected. That is not neccesarily a bad thing though unless you have incoming links. You will also take an seo hit until all of your new urls are indexed.

Dbseo does it pretty seamlessly though and will redirect all the Vbseo urls to your new ones. Great product.

I think the Google algo. penalizes for all those 404 errors. After a year I still have over a thousand after changing forum solutions. And this is despite submitting a sitemap. Google seems to be reluctant to reindex the site. At least with mine... I consider a year pretty reluctant.

Are your new urls indexed? If so then you are reindexed. it is just that your old urls have not been removed. Chances are some of them are linked elsewhere. be sure to check in webmaster tools those erros and where they are linked from.

if you want your old ones removed you can submit them through webmaster tools and block them with robots.txt.

Here's a dirty little trick you can use to get those pages indexed. Put adsense on the site.

It makes the adsense bot crawl the page everytime someone visits it without a adblocker & that information gets passed down to the search part of google.

Thanks for the tip, I had disabled ad sense after traffic began a steady decline for two weeks. After I disabled it the site recovered in a week. Either people didn't like it ..... or there's something about Google. :)

I have honestly never experienced this but people have been debating this for awhile. I am not sure if this is the case or not. Do you have any resources on this that it has been verified?

--------------- Added 30 Jan 2016 at 01:10 ---------------

Plus I am sure the newer posts are indexed. it is most likely just that the old urls are also indexed still which is the reason for the errors.. I do not think adsense would fix the errors and remove the old urls. :)

Are the newer urls indexed?

My new urls are indexed, but it is the old ones that are still listed after a year in Google search. Again, there are close to 1500 of them. I haven't had the time to go and get rid of them one by one in Google tools. There should be an option or is there... to do them all at once?

Ok, in that case go view the errors and click on the url. Click on the tab that says linked from.. remove those from your site.

Make sure they are removed from your sitemaps. Delete and regenerate and resubmit.

Also, these may be showing in webmaster tools but if you search for the url in Google are they still showing?

Once you are done with this select all the errors and mark them fixed.. That should remove them. They may pop back up though. I doubt you are getting dinged though for this type of error especially if you have a decent error page set up.