Drupal system problems

[Zholl]

Hey there, we recently migrated team2996.com to a Drupal system (I know I said a while ago we would do Joomla, but someone had some experience with Druapal), and we are having some trouble with the site. I'm not sure when it started, but I noticed today that anything past the homepage 404's on me, to the point where I am unable to even sign in to the system (I have verified this in multiple browsers on two different networks, so it shouldn't be an ISP problem). This happened once before, but I can't remember if it fixed itself or not last time, or if that was another episode involving just the sign in. Has anyone had experience with this kind of a problem before, and does anyone have any suggestions on how to go about avoiding this in the future, since I'd rather not have to reinstall the Drupal system every other month, nor would I like to migrate to yet another system after having gotten this one running