Hi Michelle1111z,
Thank you for reaching Microsoft Community.
I'm sorry to hear about what happened to your Surface Studio (1stgen) that it is not turning on anymore. Considering that you have done all troubleshooting needed including taking the device to a technician and replacing the power supply, we can conclude that this is already a hardware issue on the device. However, for service or replacement, I'm sorry to inform you that Surface Studio (1stgen) is already discontinued and thus, we no longer have any service or replacement option available for the device even the paid out-of-warranty replacement option is no longer offered.
Kind regards,
Marrion