post edit page edit url and add category not working

Malware caused havoc until found and removed. I now have a problem with altering (edit) the url for a post I created post mal… (url edit feature doesn’t work for older posts either)
The add category does not work either.
On the way to this present problem I changed the wp-content to 777 and disabled plugins. edit, etc worked. That was yesterday. Today problem has recurred. I tried to reactivate the plugins and hit error code for one plugin and a closeout of access. (cbengine) I fired up Filezilla and sliced the plugin ( which had been rewritten somehow to cbengine-disabled) out.
Tried again with activating plugins, two more slices, and now I can easily access the admin area, but the edit url feature does not work.
So, had a look at wp-config.php. Nothing obvious (that was where the malware code was placed) but removed the multisite coding as have decided to use cpanel subdomains.
Can still access the admin area, but no go on the url edit (nor add category).

Any clues, anyone out there???

btw – passw, salt, cpanel security all changed.