"As cybercriminals become more sophisticated, there is simply no way for customers to protect themselves against threats unless they update their systems", Mr Smith said.
More than 75,000 similar attacks reportedly happened in nearly 100 countries, with Russia, Ukraine and Taiwan hardest hit, according to the cybersecurity firm Avast. New versions of the worm are expected, the experts said, and the extent - and economic cost - of the damage from Friday's attack were unclear.
Fortunately, a 22-year-old British researcher and 20-something American security engineer discovered a "kill switch" and unregistered domain that halted the attack, reports the Associated Press.
"If you have a scheduled appointment you are advised to attend as normal unless you are told otherwise". Companies across the company are expected to be running checks and updating software today.
Europol executive director Rob Wainwright had warned on Sunday the situation could worsen when workers return to their offices on Monday after the weekend and logged on.
"It seems inconceivable that organisations such as the NHS are prepared to jeopardise highly confidential patient data or critical infrastructure through inadequate cyber security that relies heavily on out-dated anti-virus technologies, when effective alternatives like file-regeneration are available".
Cristiano Ronaldo explains secret to goalscoring form
Real's title aspirations undoubtedly rest on the shoulders of the 32-year-old, who's netted 13 goals in his last eight games. "I don't feel like we're the champions yet, we still need to pick up more points and keep on with what we're doing".
Tejas Express all set to run from May 22
Although the 19-coach train is created to run at a speed of up to 200 kmph, the existing track-related restrictions pose a hurdle. Apart from Mumbai to Goa service, Indian Railways plans to run Tejas Express from Delhi to Chandigarh and Delhi to Lucknow soon.