Unfortunately, it seems that memory is the main issue. However, I cannot open "Utilities" under Hard Disk at all. So, defrag, repair, expand, etc. must run through terminal prompt. This is kind of annoying, but I did run those three commands just fine from terminal. Other than those two inabilities, everything else works.
Let me reiterate, I can do the memory changes and the "Utilities" when using Windows 7 x64 as a host. But, Xubuntu 12.04 x64 acnnot do so.