Edit: This is all fixed now, had updated the database password but hadn't updated the connection info in the config file on my site, hence the problem. If a mod sees this please feel free to delete the thread!
So my website www.TPReview.co.uk has suddenly fallen afoul of a bunch of 500 Internal Server Errors to the point where I can't even access the dashboard at all. It runs on Wordpress and is hosted by fasthosts so I have access to the MySQL database and file system and everything, but to be honest I don't often poke around in there.
I've tried renaming the .htaccess file, using fresh wp-admin and wp-includes folders,renaming the plugins folder and accessing the site from loads of different computers. Seems sometimes some computers can access the main page and the posts, but none can access the login page (www.tpreview.co.uk/login) or any of the dashboard.
Contacted the hosts and they originally said it was because the 150mb MySQL database was full so I should buy an upgrade. I was a little uneasy about this because I'd heard 150mb was plenty of space, but as for some reason logging on to the database wasn't working (it said my username was logged in too many times) I couldn't do anything about it so I paid £30 (which will be £30 a year) for the upgrade to 300mb. This didn't solve the problem at all. I managed to access the database today and saw nearly all the space was taken up with spam comments and their metadata, so I've got rid of all of that and asked Fasthosts for a refund on the database upgrade as they told me that was the cause and it wasn't, plus they should have known my site doesn't need anything like that kind of space.
Anyway now I'm still stuck with a barely functioning site that I can't add anything to or change. Any ideas on things to try? The hosts are being particularly slow in responding and I really need to get it up and running asap. Also I'm kind of an idiot when it comes to any of the PHP coding or databases so I migth need some hand-holding if anything needs to be changed there.