Help, hosting account suspended because of spam!

[ArgylePhoto]

I originally posted this over on vB.com but I'm not getting much response so wondering if anyone here has any ideas..



My hosting account was suspended yesterday because of spam originating from my forum's index.php file/page. The email they sent me says:

"Your account has been suspended because spam has been sent through your scripts, i.e X-PHP-Script: www.**********.co.uk/forum/index.php"

I don't even know what that means tbh, apparently that script/page/file/? was sending out thousands of emails. I was running 3.7.3 but have now been given access to upgrade and have upgraded to 3.7.5.

Does anyone have any idea if that will have solved the problem?

I need to get the site back up asap but don't even really know what I'm looking for.

Please help!