Window slides down

It definitely sounds like you need a new balance. This is a spring-based mechanism that regulates the operation of the window.

We sell a ton of different balances so there's a good chance that we can help, but before I recommend anything I will need to see a clear picture of the balance in question. That will give me a good idea of what you have and whether or not we can help.

Please note that I may require more information and photos after that, but I'll have to know what to ask for, first.