So I have MacBook pro 13" 2011. (4gb ram, 350gb HDD, intel i5) soon after the Yosemite upgrade the system became unresponsive and slow, even the cursor lagged and boot would take a long time. So I decided to format and reinstall OSX from the recovery using the internet. now here is what I did- booted into recovery, and formatted the mac os extended (journaled). After that I reinstalled Yosemite, but while the installation almost at 95 percent it got stuck , I waited 2-3 hours but there was no activity. I checked the install log the last message was 3 hours ago, I don't remember the message but it was an error. so I decided to reboot in recovery again and restart the installation again. Now, if I try to enter the recovery mode using command+R ,the apple logo appears and the loading bar but it gets stuck at around 40 percent , I tried atleast 10 times and waited for 3-4 hours but it was no good I also cleared the pram with command + option+ P+R, still everything is same. if I boot normally I get the prohibitory sign. I also cleared smc what should I do... please respond soon. thanks. PS. I don't have any other mac device or any disk with mac os. I'm using a windows 10 laptop right now.