Q mobile A500 men downloading error insufficient space

Q mobile A500 men play store se download karne jaata hun tou error aata he "insufficient space" jab k iss men cd card men bhut space he...... aur "setting...app...."men move to sd card ka option band he means show tou karta he lakin press nahi kar sakte.kisi ne kaha he k ye mobile flash karwaana paregaa.... isska kisi k pass solution ho ya flash ka easy procedure maaloom ho tou plz help me