My SEP licence was ended and I want to remove from my pc

Hello,

Semantic Endpoin protection 12.1 was installed on my windows. I dont remember how i installed it. I want to remove my laptop. I tried manuel instruction but it doesnt work. When I delete sep from regedit it give error. I can not stop sep services. I can not stop working sep. Product information is ob the below. 

I am going crazy. I want to get rid of this application without reinstall windows.  

<serial_id>88003893.7</serial_id>
<serial_number>M2087147102</serial_number>
<product_name>Symantec Endpoint Protection 12.1 90 Day Temporary License</product_name>
<sign_date>2015-01-05</sign_date>