Microsoft's new OS 'Windows 10' is a free upgrade for people who have a licensed copy of Windows 7 or Windows 8.1 installed on their PC. But, owners should also be aware of a new email scam that claims to offer the same upgrade, which in fact is a way for hackers to get people to install a ransomware program. Cisco has discovered that the email is making its way across the Internet via an IP address located in Thailand. The email claims to have an installer attachment that will give PC owners the Windows 10 upgrade. Once you run the programme, it tells you that 'Your personal files are encrypted by CTB-Locker' and you will only be able to decrypt them once you have 'paid the ransom amount'.