Experts warn novice surfers away from the web...The rapid spread of the Nimda worm has slowed but it continues to rack up high profile casualties and the associated clean up costs are beginning to mount. Reports have come in that casualties include Dell web servers, Demon's internet servers and the Australian Parliament in Canberra. Software giant Microsoft has, however, refuted claims that a FrontPage website has the Nimda worm embedded in it and was infecting surfers. A senior researcher working in a data analysis department of San Diego's Supercomputer Center, said 130,000 Web servers and personal computers in the US appeared to be infected with the bug as of Tuesday afternoon. Network Associates estimates Nimda's economic impact has reached nearly $531m already, based on some two million machines being infected worldwide. Code Red in comparison was reported to have cost an estimated $2.6bn to clean-up. Alex Shipp, chief AV technologist with MessageLabs said: "Nimda is a nightmare from a clean-up point of view. You have to also make sure to re-set your security, otherwise your system is wide open to a second wave of attacks and these could include Trojan or hacking attacks." Some virus experts are warning novice surfers to stay off the internet as Nimda can be picked up from infected websites, aswell as email, if they do not to update their software protection themselves. The Nimda worm, which attempts to exploit 16 different holes in Windows 2000 and PCs running Windows 95, 98, Me and 2000, was thought to have originated in South Korea.