my thought on all this is - you are using wubi which installs inside a virtual file in windows. so if you have problems with windows you will have issues here. additionally wubi is not necesserily as fast as dedicated install. furthermore wubi is only ment to test and as a chance to give users to easilly try out the system withouth any major system changes.
so i suggest you try again and this time with propper side by side dual boot. or only linux if you htink you can handle it.
and one more thing - there is no need to download xubuntu, reformat, reisntall... to see how a different desktop looks/behaves. you could have just searched for xubuntu-desktop in software center and install it. that would install Xubuntu to your computer. note that you might get some services doubled - e.g. network monitor form gnome and network monitor form xfce and such. but you can see hwo it looks like and behaves and oyu can later remove the gnome if you wish by copying a few commands into the terminal (very fast mehtod) or finding packages in package manager and uninstall those one by one.