Factory reset Cynogenmod 10 OS in LG P-500 makes applications crash

Previously my friend installed **cyanogenmod 10 OS** in my **LG P-500** phone. It was working so superb. I had to do **factory reset** to the phone for deleting some files, after which I am **unable to open any of the applications, not even browser and play store.** I installed **Dolphin browser**, which is **also getting crashed** in 1 min itself. Now I decided to re-install the OS. All zip files required for installation are with me, but I don't know **how to install Cyanogenmod OS** .