Mail is not sent

Hi, I've found a lot of threads about mail problems in Drupal since having some myself, but most threads are very old.

I installed Drupal 6.13 on 3 sites, two in folders and accessed via subdomains, but all on the same host. I installed various modules to see how they functioned and if I really needed them, and carefully uninstalled them by 'switching them off' before deleting their folders on the server. But as time went by I discovered email problems.

My first issue was when trying to add a user via admin, it failed with some sort of array error. When I registered a test user manually (the way a visitor would) it worked, but no email was sent. The sites on the subdomains were worse; their contact forms wouldn't send mail at all. I assumed it was something to do with the fact that they were in folders and not the main domain's root folder, and my very patient hosting company has spent days trying to sort it out with me. (In case you're curious, they're kNet Hosting in the UK, and their technical support is just wonderful compared to others I've used in the past).

I spent hours and hours getting SMTP Mail working, and Yay! - the contact form worked on a subdomain. Only there was a problem; I'd told it to send a copy of the email to me. It didn't arrive, though the email to the test user did. Finally, I created a new folder and subdomain, and did a new install. Everything works superbly. I can create new users in admin, emails arrive. On self-registering a test user, emails arrive. Using the site-wide or personal contact forms, emails arrive.

My conclusion? One or more of the modules is seriously screwing things up. This is backed up by the fact that on all 3 sites, after carefully uninstalling various modules, the menu system went completely crazy. I have 3 copies of various menus, some with a 'reset' link and some not, and no matter what I do with them the duplicates will not go away. In the end I had to put 'AAA' at the start of their names so I could identify them in the database, then went and manually deleted them via my hosting cPanel.

Now let me say before the 'negative' comment, that I appreciate how much time people put into developing free modules for me and others to use. But good grief, if they do THIS to Drupal, how many users are they going to put off by screwing a pretty good working CMS system before they've even got it up and running? Personally, I think if someone doesn't have a damned good technical background in programming they ought to say so in their module write-ups. I now have to go through every single module I want to use, one at a time on a 'blank' site, testing whether I can add users without errors, and spending time manually registering them and checking that emails arrive, as well as testing the contact forms as admin and as a lower permission user. HOW long is that going to take me on top of the entire week I've spent trying to find out what was wrong with Drupal, when NOTHING was..?! Sheesh.