...you mention that it will not open any files, this indicates that quark does in fact launch?

...with this fact  can you create new quark documents?

...have you tried booting in safe mode (shift key on startup), then restarting again to clean font caches?

...are your font folders packed with fonts you rarely use? If so, move them out apart from the system critical fonts, the ones installed by the OS...

...have you removed this file from user > library > preferences "com.quark.QuarkXPress.plist"?

...and this entire folder "Quark" from the same location?

...if not try removing those...

...does quark work fine without the suitcase extension loaded in the quark application folder > extensions?

...does quark run fine when in "safe" boot mode, but not in normal boot?

...are you running 10.4 OS, and have you tried creating a virtual printer, then launching quark? http://kb2.adobe.com/cps/329/329662.html

andrew

...unless you have already, you may also want to update to 6.52:

http://downloads.quark.com/Details.aspx?fid=122&;

andrew

...if all the above fails, try creating a new user account, login and see if quark works fine in that user...

andrew

...one other thing that comes to mind is:

Open the "For System" folder in the Quark application folder. Double click "QuarkXPress Components".

Try deleting all preference files again. Try opening documents again.

If still no joy, check permissions on your Quark application folder. Owner with system (R/W). Group with staff (R/W). Other (R/W). Apply to all folders/files. Try opening documents again.

If that still doesn't work make a folder inside your Quark application folder called "Preferences". Try opening documents again.

andrew