MacBook Pro Mid 2012 freezes when plugged in

Hi. My Mid 2012 MBP which runs on Yosemite 10.10.2 keeps freezing even when just browsing on Chrome so I uninstalled Chrome and used Safari. I was still having problems after switching browsers so I restored my device to its factory settings but the restore did not solve my problem. All this time my device was plugged in so I unplugged it and tried to browse. It did not freeze or crash. I read the forums and found out about the SMC reset and a NVRAM reset but my device is still freezing when plugged in. I am typing this while my MBP is unplugged. Please help.