First, are you using the latest version of TurboActivate (currently 3.4.6)? See the changelog for why:
- [...]
- Fixed some false-positive virtual machine detection on Windows.
- Fixed Microsoft Surface Pros being detected as virtual machines.
- Fixed in some rare cases the wrong network device was used in the hardware fingerprint.
A good rule of thumb is always try the latest TurboActivate. We are continually developing and improving our products.
If you're already on the latest version, make sure the customer doesn't have Hyper-V enabled (google for how to check / disable Hyper-V). That's a virtual machine (meaning their installed operating system is actually a "guest" VM instance -- there is no "host" VM with Hyper-V -- it's just the way it works).