Scammers are making thousands of cold calls to homes and businesses claiming computers have faults and the problem can be fixed online for a fee.
Computer software service fraud chalked up more than 12,000 reports to Action Fraud, the UK government scam buster service between June and November last year.
The number of attempts to trick victims is likely to be much higher as few of the calls are reported as fraud.
The National Fraud Intelligence Bureau (NFIB) is warning that any calls from organisations such as Microsoft, TalkTalk, BT as well as the Windows Technical Department are bogus.
They also explained the scammers ripped off their victims to the tune of £691,450 with some victims losing up to £6,000.
The fraudsters take over computers by asking for passwords to allow them remote access to Windows computers.
They then fix the made-up problem charging a fee of £100 to £300.
“Once they have access to a victim’s computer, they often go back and grab larger sums from their bank accounts,” said a NFIB spokesman.
“If you receive one of these calls just hang up because anything from there on is a con.”
Report a computer software service scam to Action Fraud by calling 0300 123 2040 or online.
Warnings about bogus advisers
Here are the latest bogus financial advisers listed on the Financial Conduct Authority (FCA) web site:
Dealing with an unregulated firm
If you buy shares, save money or invest with an unregulated firm, you lose any protection offered by the Financial Ombudsman and the Financial Services Compensation Scheme. Broadly, you have no independent place to complain if the deal goes wrong and are unlikely to win any compensation.
Checking if a firm is regulated
Go to the Financial Services Register to check if a firm is regulated in the UK.
Reporting a suspected bogus adviser