Nearly all my plugins have stopped working

Yesterday I changed my blog URL to make it look as if my wp is in the root directory instead of another folder by changing the settings in the admin panel and moving my .htaccess and index.php.

Then I noticed today I’m getting a lot of spam coming through, and that Bad Behavior and Challenge aren’t working (if you try to post a comment on my blog and leave the spam question blank, it accepts it). My theme switcher plugin isn’t working either, though as far as I can tell Cystats is.

I haven’t upgraded or touched anything else, Google couldn’t find me anyone with the same problem, and I’ve tried deactivating, uninstalling and reinstalling and activating with no difference. I can’t find anything in the settings which suggests I need to change a line of code or something to tell the plugins there’s a sort of redirect going on.

This may be somewhat related to another problem I’ve had for a while where certain pages and actions will randomly and inconsistently redirect to a 404 in the admin panel (despite the pages being CHMODed to 644 and existing in the right places and me checking for hacked code).

Any help or suggestions would be very much appreciated. I’ve tried everything in the plugin troubleshooting list, so I can only assume it’s a problem with the blog url vs real url.

My site address is https://blossom.nu