Using WinRAR, I deleted all the files related to tekkit and the technic launcher. it took a long time! but! It worked!!! I redownloaded the launcher and it said I don't have it already installed, asked me if I wanted to change download folder, said no, waited, and it worked!!! in did reset my tekkit modpacks and stuff but it worked! its another way to solve it. and don't worry if WinRAR says "your trial period is up, please buy licence?" because WinRAR will still work. make sure you haven't tried to run tekkit or it wont delete. restart then delete the files.