Windows 7 virtual machine aborted!!

[Emmaka]

I'm running a windows 7 virtual on Ubuntu, with which I attached my other (old) windows 7 VM's HDD(vdi file) to copy some important files. Then I shut down my VM, removed the other VM (the old one), removed the vdi file from being attached to my VM, increased memory and processor, changed the boot order - basically just unchecked the floppy. Then I started my VM and it was just a blank black screen. I tried to close it but I get the dialog box - virtual box is not responding, So I choose Force Quit, but it wouldn't quit. I shut down my computer, it wouldn't even shut down. So I'd have shut it down with the turn off button. And then when I opened my virtual box, it shows VM's aborted. Since it's like this. Doesn't work.

Please help me debug and fix the problem. Thanks in advance.
I have attached the log file.