Just a friendly tip off about phone calls saying they are Microsoft Certified engineers. The call comes from India (unfortunately) and they claim your computer has told their servers that there are issues on your computer.
They will ask you to access the "Event Viewer" and tell you how to do it. They will then say they can show you how to fix it and ask you access a website called www.microsoft.comuf.com. HANG UP. They will try to sell you software.
Mircosoft do not call you to give you technical assistance. You call them.