Help please, bootmgr missing' and 'windows cannot find a system image'

So I've the c & d - drives sorted, and it has now moved onto this familure screen where is stays and fails to expand. I've tried this a couple times.

Then it comes back with this..

x64 english

so that's as far when I originally tried to reinstall the operating system. That error message, its like and old friend.

It's just bad media. Why do you try to reinstall?

So the computer was running slow at times and I thought reinstalling the OS and drivers from scratch would solve any underlying issues it had. Not my best laid plan, agreed. Now it isn't working!

disk errors are not the reason for reinstall?
memory errors?

no other errors, it was just running slow and occasionally firefox would crash and flashplayer would stop working

You're trying to install win7 x64 english. But is it home premium, professional or ultimate?

Its windows 7 home premium 64-bit.

If it is a media problem, why won't it boot up?