Can't post….'Submit for review'

I’ve got this REALLY irritating issue with my WordPress site, that just happened at random….meaning I can’t add a new post, edit other posts or do loads of other actions such as create a new admin, delete comments etc.

When I go to create a new post the only option is to ‘Submit for review’ or ‘Save Draft’….when saving it a draft it just disappears.

I’ve tried many things to solve this including:

– Deactivating plug-ins
– Deactivating theme (back to original)
– Checking permissions
– Checking space

In the MySQL database, for some reason it won’t let me ‘repair tables’ for any of the data… it says ‘INSERT command denied to user’

I’ve also tried checking all the primary keys for auto_increment…..it seems that they do have auto increment BUT I don’t really know what I’m checking/doing so might be wrong haha.

PLEASE is there anyone with any ideas of how to fix this?? (and can explain V simply?) I really need the site up by next week, and so stressing out!

Also…I did update wordpress fairly recently but haven’t updated to WP 3.9.1…but it doesn’t seem to let me do that either!!!

THANKS!!!