According to a Newegg site video linked to below, you can use an Administrative Command Prompt and type the following command to find out if TRIM is turned on or not.
fsutil behavior query DisableDeleteNotify If
DisableDeleteNoftify=0 then trim is turned on. I will have to state, I ran it on my system, without an SSD, and it shows 0.
Newegg.com - SSD, Solid State Drives about 2/3 the way through.