My Hamilton Bay fan that I have had for 3 years changed speeds from high to low when operation last night. It will not rotate in any other position. I have tried turning it off and on by both the chain and wall switch. What can be done to solve this issue? My last ceiling fan lasted over 20 years. Please help.

Do you mean hampton bay? You can contact them via this thread https://www.askmehelpdesk.com/electr...ons-46738.html If there is no remote your pull chain switch has failed and needs replacement

Sounds like a bad capacitor. It's not a remote fan, right? Are you using a wall control?

Ceiling fan capactors - troubleshooting and resources - Ceiling Fans N More