I don't think you understood my thought process on one of the levels - it wasn't to do a new install, it was to migrate his existing laptop to a VM - and you can migrate a system to a VM, and if he isn't disposing of his existing key, he should be ok. Now, a fresh install (whether it be vm or bootcamp, that becomes a separate issue).
If it wasn't legit to migrate a machine from physical to virtual, VMWare wouldn't have a tool to do it (vmware converter), Parallels wouldn't have a tool to do it (Parallels Transporter) and neither would microsoft (to migrate a physical box to VirtualPC, but I can't remember what it's called and it is no where near as advanced as vmwares or parallels tool). I'm not suggesting he do something illegal - and it shouldn't be if he keeps his license key and either keeps the laptop or destroys the data on the hd (or removes the hd) as long as he keeps the key. Now, if the OP converts his machine from physical to virtual, then sells the machine the way it currently is (with key, software installed, etc.) then the OP would definitely be violating all kinds of EULA's and laws.
The only major flaw with it is you're migrating an existing machine - if your current install has issues (whether it be spyware, virus, too much stuff running, etc.) then those issues will obviously follow you. There is also a potential problem with drivers (ie: if you have the soundmax HD audio drivers currently installed - do a conversion, each time you boot the VM it will complain about the drivers and there not being the appropriate hardware, but it won't let you uninstall because it complains there is no compatible hardware so the software won't run).
Not everything violates EULA, and if migrating a physical machine to virtual did violate, a lot of businesses would be in trouble, including VMWare, Parallels and Microsoft (for violating their own EULA
). Now I did put in my original post about legality might be in question - and that was referring to what the OP's EULA might (or might not) specify.