About 150 million computers are used every day in China, but six out of ten computers have problems such as slow running speeds, according to a report released by a major Chinese computer security company in Beijing on Wednesday.

Excessive numbers of "startup programs" lead to slower operating speeds, resulting in lower overall efficiency, said the report, which was released by Qihoo 360, China's largest free anti-virus software provider.

About two-fifths of the 10,000 programs most commonly set to start running when users' computers boot up, including web browsing and word processing programs, are considered "useless" by Qihoo 360, according to the report.

The report said that the average computer in China takes 56 seconds to fully boot, with about 380,000 computers taking more than 5 minutes to complete the process.

"Some of these programs can be useful, but it is unnecessary to automatically run these programs at start-up," the report said, adding that "autorun" programs, which automatically start running when the computer boots up, are often the targets of malicious computer hackers.

Malicious browser helper objects (BHOs), system junk files, trojan software and pop-ups are the biggest problems for computer security in China, the report said.

The number of Chinese users who have installed Qihoo 360's free security software topped 328 million by the end of January this year, according to iResearch, a computer data analysis company.