raj576 wrote:
Also my hdd is formatted to journaled buy ssd in APFS format.ssd was not formatting when it was newly installed so i removed it can pluged it in usb with caddy case and then formatted.
This could indicate a defective internal hard drive cable. Or it could be an incompatibility with the laptop's SATA controller and the SSD. Replacing the internal cable would be the next step.
Is there any way that i can install macos high sierra on my ssd for faster boot.i tried installing by thumb drive which i previously used to install Hsierra but this time when i chose that on boot menu many apple logo appeared on whole display and blue background .it was like my mac malfunctioned so i haven't used that drive..
Creating a macOS USB installer is the only way now if you are using Mojave. The graphical issues you are seeing is either due to a defective GPU which is common on the 15" & 17" MBPro 2011'2 or you have a defective LCD panel.
All of these issues/difficulties are pointing to hardware issues of some sort.
Once you boot macOS, go into the Startup Disk in System Preferences to make sure the SSD is selected as the boot drive.