2001 Sentra b15 with sr20de Wont start

[sr20detboy]

if anyone can help me out I have a major dilemma. My 2001 Nissan Sentra se with 2.0 engine keeps frying the ecu. the car will not start it ran great until one day I pumped some gas and tried to start the car it cranked but would not start. I Noticed on the dash when the key was turned to the on position the cluster was not working gas meter didn't move temp meter didn't move nor did the mileage display show anything. I looked over somethings to determined the problem and noticed that the ecu was fried. so figured my ecu was bad I bought another ecu plugged it up and it started to smoke. Can anyone help me determined what causing this. any help would be greatly appreciated thanks.

[sr20detboy]

ECU: MEC22-530 A1 0X25