Do not purchase any software or services.
Ask if there is a fee or subscription associated with the "service." If there is, hang up.
Never give control of your computer to a third party unless you can confirm that it is a legitimate representative of a computer support team with whom you are already a customer.
Take the caller's information down and immediately report it to your local authorities.
Never provide your credit card or financial information to someone claiming to be from Microsoft tech support.
If you think that you might have downloaded malware from a phone tech support scam website or allowed a cybercriminal to access your computer, take these steps:
Change your computer's password, change the password on your main email account, and change the password for any financial accounts, especially your bank and credit card.
Scan your computer with the Microsoft Safety Scanner to find out if you have malware installed on your computer.
Install Microsoft Security Essentials. (Microsoft Security Essentials is a free program. If someone calls you to install this product and then charge you for it, this is also a scam.)
Note: In Windows 8, Windows Defender replaces Microsoft Security Essentials. Windows Defender runs in the background and notifies you when you need to take specific action. However, you can use it anytime to scan for malware if your computer isn’t working properly or you clicked a suspicious link online or in an email message.
Learn more about Windows Defender
There are some cases where Microsoft will work with your Internet service provider and call you to fix a malware-infected computer—such as during the recent cleanup effort begun in our botnet takedown actions. These calls will be made by someone with whom you can verify you already are a customer. You will never receive a legitimate call from Microsoft or our partners to charge you for computer fixes.