Internet recovery mode not working

I have got macbook pro early 2011 model. Initially it came with Mac OS X Lion. Later on I upgraded it to Mavericks. Recently I thought of upgrading it to Yosemite which I did. On successful installation I realised that It is extremely slow and found out that it is encrypting my whole hard disk. I left it for hours and hours but it looked like it stuck on that process. And also did not allow me to stop the process. I turned off my macbook using power button kind of hard stop thing. When I tried to turn it on, it stuck on safe mode and nothing was happening. I could not log back in and I tried all the diifferent methods like PRAM reset, safe mode, disk utility tool to repair the disk but nothing seemed to work. Luckily I had backup in Time machine from last year which restored my system back to Mavericks. I started using it and it was working fine. Yesterday while closing my system I used Power button and did that forced shut down kind of thing again and since then it is not turning back on properly. it keeps going to safe mode. From safe mode I tried to restart the system but since then it stuck on Grey Barred Circle thing.

I decided to use Internet recovery method when all other methods failed including safe mode, pram reset, single user command. It looked like I will be able to restore my mac using my back up on time machine in external hard disk but it stuck on 85% twice. And now when I am trying to re-install the orignal version of Lion OS X which came with my macbook using internet recovery mode it is giving me an error, "you cant upgrade this version because newer version is installed". Please help me. thanks