what specific problem led Rome to change from a monarchy to a republic?

One specific problem that led Rome to change from a monarchy to a republic was the oppressive rule of the last Etruscan king, Tarquin the Proud. He was known for his tyrannical behavior and brutality, which caused resentment among the Roman people. This eventually led to a revolt and the establishment of the Roman Republic, with a system of checks and balances to prevent any one individual from wielding too much power.