I would start repairing the system drive with the disk utility. Then copy a template from
to your Desktop.
Choose a small project such as 'StereoMstr', dubble click on the copy and then see what will happen. You don't want to save this project to start with.
Also, are you on 32bit or 64bit? Most probably your project is corrupted or a 3rd party plugin is acting weird. Did you by any chance instal any new 3rd party plugins recently?
Songs have stopped loading- get as far as Channel EQ then sticks - any thoughts? Logic Studio not responding
I presume that you have Logic Preferences set to open the last project you are working on? If you have a problem project, this would prevent you from opening Logic at all.
First, try starting Logic and immediately hold down the Control key to disable the audio drivers. Logic should then start up ok.
If it does, make a new empty project, re-enable the audio drivers (Preferences:Audio) and see if the new project works OK.
Depending on the results, further troubleshooting may be required.