If you are one of those people who spent close to $2,000 on a shiny Sony Vaio notebook, you should know that your ability to run XP Mode in Windows 7 has been deliberately disable ... by Sony.
While the Intel Core 2 Duo mobile processor that Sony uses inside the Vaio supports VT virtualization, Sony decided that because of the risk of malware, combined with little interest from customers, to disable this feature in the BIOS. To make matters worse, there's no way for the average user to re-enable VT!
According to Sony senior manager for product marketing Xavier Lauwaert, VT hadn't been enabled because they had received "very little if any requests until recently" and that engineers were "very concerned that enabling VT would expose our systems to malicious code that could go very deep in the Operating System structure of the PC and completely disable the latter". What made matters worse for Sony is that this issue exploded in the comment sections of a blog post on the Windows Team blog site in which Sony was talking up Windows 7.
According to Lauwaert, Sony will "will enable VT on select models" but it seems that Z-series Vaio owners will miss out.
I've stopped recommending Sony PCs several years ago. The company seems too focused on consumer electronics and music to product a decent professional-grade computer. This disabling of VT support just reinforces my lack of faith in the company.
Bought a Z-series Vaio and desperately need VT enabled? There is an unofficial patch available. I've not tried this, there are warranties and it could cause all sorts of mayhem, but if you're stuck, it's worth a try!