Window won't stay up

It looks like you need a new coil balance system. Coil balances are spring mechanisms in the window jambs that regulate the opening and closing of the window. These are modular systems, meaning you can replace each part individually; undamaged pieces you needn't replace. The pivot shoe these balances attach to is our 15-180. Those clips around the balances are our 15-181 and 15-186, respectively. The coil balances themselves are our Series 190 springs. Let me know if you have further questions. The video below shows how to remove and replace a very similar system.