Soar (1997)

A wealthy industrialist who refuses to doctor his product is killed by his corrupt business partners (the great trio of Danny Denzongpa, Dilip Tahil, and Prem Chopra), and his share of the company goes to his daughter Versha (Rekha). When she begins to figure out the truth, the nefarious partners conspire to have her locked in a mental institute--but that's not enough to stop our heroine, who makes some new, insane friends and returns with revenge on her mind.