US co tells PC makers: halt China anti-porn software

* Makes demand on Dell, HP, others

* Asserts software contains stolen code

LOS ANGELES, June 18 (Reuters) - A California company accusing a Chinese rival of stealing its code for anti-pornography software has demanded that U.S. PC makers Dell (DELL.O), Hewlett-Packard (HPQ.N) and Gateway stop shipping computers loaded with the program "Green Dam".

Solid Oak Software Inc, which said it found pieces of its CyberSitter Internet-filtering software in a similar Chinese program, said it had faxed cease-and-desist letters to Dell, HP and Gateway, and to the U.S. units of Sony (6758.T), Toshiba (6502.T), Acer (2353.TW), and Lenovo (0992.HK).

Solid Oak executives have warned that they may seek a court injunction to try to stop PC manufacturers from shipping to China machines loaded with "Green Dam", developed by Jinhui Computer System Engineering Inc and now mandatory on PCs sold in China, the world's third-largest economy. [ID:nN13119455]

"With the cease-and-desist letters, we've asked them to not ship the units as well as make accounting for any units that had been shipped," Solid Oak spokeswoman Jenna DiPasquale said.

She said that Solid Oak had not heard from the PC makers.

"We're really hoping to have an amicable" resolution," DiPasquale said. "This isn't their fault, it's just something they've been asked to do."

The Chinese government has required that all new computers made or shipped by July 1 come with "Green Dam" pre-installed, to protect children against pornography. "Green Dam" filters out words, images and Web addresses.