Yeah, the safe mode is the console - which I suspect it spit you out to when it said "no screen found" - a common error message in X. Only thing I can really suggest if you don't know your system very well is to check on either /etc/X11/xorg.conf or /etc/X11/XF86Config-4, depending on whether you use XFree86 or xorg. You probably changed to an unsupported resolution. Switch it back in that config file. Then type "startx"
A real Linux professional needs no GUI to repair the X config files, just use vim in the console
If everthing else fails, boot from CD-Rom (AFAIK Mepis can do that, or use Knoppix or similar) and repair what you need to repair. Next time, make a copy of your config files before changing them, just in case something breaks after your changes.
Also incase you aren't familiar with the command line file editor (VI) you move around using the arrow keys and delete text by pressing X key to type text in you will need to press I you will then have to press ESCAPE and then type :wq!
then try either CTRL + ALT + F7
simply type startx
this will load a generic driver which will let you get into the GUI once in look for the configuration utility and change the driver as recommended.