this has worked for me before for vanilla minecraft. if the world file is still in your %appdata%/.minecraft/saves i just made a new world and named it the exact same thing with the seed you used (if it had a seed) and it actually gave me the world back
the thing in the top right corner of the launcher should have a drop down arrow where u can select what you play. u must have it set to vanilla just change it over to technic
in the screen tht has singleplayer, multiplayer, texture packs, etc theres a thing i can click on called mods and it tells all the mods im running is there anyway i can change my mods with that?