(EDIT: as dtr1au just said) You could install shiva in a virtual machine (f.e. vmware player: )...
At this moment i must share my windows 7 machine and my ubuntu box is my only option (in anticipation of the 2.0...ehm no, this is not the moment to talk of the 2.0

)
I use vmware player, with an emulated dual core processor and 512MB of memory on a (real) amd 3 core phenom and 4gb of ram and an integrated ( slow like hell ) radeon hd 3200, and although the pc is obsolete the performances are decent for my needs (learning shiva/testing simple games)
If you need assistance to install/configure the virtual machine i'm glad to help you

Obviously every-time you switch from your usual windows machine you must migrate your shiva license