I have a problem booting from a hdd. I used to have it as my main drive before I bought an SSD, so I had been able to boot from it. But for some reason, now, half a year later, I can't get it to work.

I completely erased it, deleting data and partitioning (using EASEUS Partition Master), then I installed Kubuntu (without changing anything in the installer), but it simply won't boot up. It always boots the drive with Windows and when I unplug this drive, it only gives me an error "PXE-E61: Media test failure, check cable", I guess it's trying to boot from LAN.

I tried installing the system on a freshly deleted drive, without any other drives plugged in the pc, but the problems persist.

This is how the drives look now (first one has Windows 7 installed, the second one Kubuntu):

I am lost. I mean, after doing a fresh wipe and a clean install without altering anything, it should work. But it doesn't. What can be wrong here?

Thanks