I want to remotely play my turntable on my stereo system on another floor

Solution
You don't need your laptop. There are cheap ($30) bluetooth-transmitters which you can pair with your "digital stereo".
Keep in mind, however, that Bluetooth is "personal" technology, and it might not cover the floor-to-floor distance.

You can still use your laptop as "transmitter", pairing it to the stereo, but don't connect TT to the mic port. Get cheap USB sound card with line-in connector instead.
Can you be little bit more specific? Which piece of equipment is located where, and connected to what?
What is the distance between pieces?
 

The turntable is upstairs connected to an analog stereo (20 ish yrs old) and I want to connect it to the digital stereo on the main floor via the laptop on the upper floors Bluetooth to the digital stereos Bluetooth for parties. Is there a way to do this by hooking the turntable to my laptops mic port and broadcasting it over Bluetooth?
 
You don't need your laptop. There are cheap ($30) bluetooth-transmitters which you can pair with your "digital stereo".
Keep in mind, however, that Bluetooth is "personal" technology, and it might not cover the floor-to-floor distance.

You can still use your laptop as "transmitter", pairing it to the stereo, but don't connect TT to the mic port. Get cheap USB sound card with line-in connector instead.
 
Solution