Hi,
For Q2, the links provided are applicable. The license key for windows 8 which you currently have is probably an upgrade key. Many Windows 8 user have experienced same issue. They assume its full version whereas its not in majority of windows 8 buyers. Both links posted addresses this issue for fresh install.
For Q1, the sluggish ness, slowness, mouse and keyboard issue all point out towards improper / partial upgrade method.
I recommend you to have a look at
upgrading windows xp to windows 8
This addresses the post migration issue especially with network, sound and also mouse and keyboard. Basically you need to change the virtual machine template from windows xp to windows 8 as described in the article in general settings.