By James Reynolds
BBC News, Beijing
Almost one million Chinese computers were hit by viruses during last week's national holidays, state media has reported.
China has more than 130m web users
Three different types of viruses attacked computers during the holiday week, Xinhua news agency said.
It is not the first time China's web users have faced problems recently.
A Pacific earthquake damaged undersea cables earlier this year, slowing down internet lines and forcing many people to start using their old fax machines.
China has more than 130 million internet users - and last week should have been a perfect time for them to catch up with their web surfing.
There was an entire week of national holidays - known as the Golden Week - so most people were off work with plenty of time to spend at home online.
But for some internet users, there were real problems. Nearly one million computers crashed as a result of the viruses.
But in other ways, experts suggest that parts of China's computer system are working extremely well.
Recently, there have been repeated allegations that the Chinese army has hacked its way into sensitive government systems in the US and Europe.
It is a charge that China has denied.