I tried to update my site on my server from joomla 2.5 to 3 but it failed miserably. Then I restored my site with akeeba backup which was successful except for one minor detail. Since the restoration I cannot open any k2 items of create any. I thought it my be a server issue but my hosting provider looked at this and said it is being cause the k2 plugin didnt restore correctly. Any suggestions or help appreciated. Thanks

Try reinstalling K2. It will probably do the trick.
Simply grab the latest version and install it on top.

Reinstalling or updating to Joomla! 2.5.22 is not a bad idea as well.

If I try that I will loose all my site content, my k2 items and categories, I tried that and had to restore my site again

Assuming your are back on k2 with J2.5.x :
Can you see K2 data in the backend?

If not then your Akeeba backup might be configured to omit k2?

If you can see your K2 data in the backend, then there may have been some issues with k2 categories and content. Sometimes I have seen author and access values change thru the process of migration. IF you can see your K2 data then check it has access values and authors associated with items and categories.

Lastly if you can see K2 data in backend and access per item/category looks ok, check any menu items that point to K2 for broken associations - ie they might need reopening and saving

Hope this helps

Apart from what Alan suggested there is also a longshot
Repair your DB tables in case one the K2 tables has been locked and you cannot access content properly.

Finally reinstalling/updating K2 (installing it on top of the existing version) will not result in data loss.

My k2 items and categories are there and I have installed k2 over the old component, however when i try to create a new item or category or open them, my screen goes blank and I cannot do anything. I don't know why this is happening and my host said this is not a server issue Also there seems to be no issue with the database
thanks

Can you enable error reporting (Global Configuration tab) to see the actual error?

I did and it is showing no error just a blank page

Did you set it to development?
If it still does not display any errors, you should ask your host for the error_log.