How to operate double hung window sashes
VIDEO: Double hung window troubleshooting
VIDEO: The balance mechanism in double hung windows
Removing a sash...
To tilt a sash in, raise it slightly (or lower, if top sash), then release the sash retaining clips on either side; pull gently toward you.
... then repeat with top sash if desired.
Replacing a sash...
Are your window sashes mounted with closed shoes or open shoes?
Double hung windows have pivot bars on the sash which fit into shoes in the frame. Some windows have closed shoes, and some have open shoes.
For windows with open shoes:
For windows with closed shoes: