Generally :
if you install windows into a VM/sandbox you can install anything you want in there. If it gets totally messed up with virus and trojan, you can just wipe it clean and start over. It is a safe way to use downloaded stuff and surf the web. I have gotten a ton of virus/trojan just from visiting a page and not even clicking anything. There are always people that figure out exploits faster than they can be patched.
I myself do not do that, but I do have a single computer dedicated to only web - I have another install of windows in its own partition, if the one im on is messed, I will just flip and then erase the other. I really should be using VM though.
just my 2c worth