Net giant Google has recovered after a sneaky virus severely affected its search engine.
Only some UK users seem to be affected
Net security firms reported that the havoc had been caused by a new variant of the MyDoom virus.
Google confirmed it had been hit by fallout from the virus, slowing down searches, but said its search engine was not "significantly impaired".
The search engine is one of the most popular on the net, dealing with 200 million global queries a day.
First reports of the problems with the UK service started emerging at around 1530 GMT (1630 BST).
Instead of getting a page of results, some users in the UK, US and France were confronted with a server error instead. Other net users reported no problems.
In a statement Google said on Monday night: "The Google search engine experienced slowness for a short period of time earlier today because of the MyDoom virus, which flooded major search engines with automated searches.
"A small number of users and networks that have the MyDoom virus have been affected for a longer period of time.
"At no point was the Google website significantly impaired."
Google is one of several search engines used by MyDoom to find valid e-mail addresses on the net. Past versions of the virus only searched a user's own computer or address list.
The MyDoom.O variant spreads in the form of an e-mail attachment.
The attached message pretends to be from the user's net provider's or company's support team saying that their PC has been used by hackers to send spam.
Previous versions of MyDoom have launched distributed denial of service attacks (DDoS) on websites like Microsoft and software firm SCO.
Infected computers are used to bombard target websites with bogus data packages that utterly paralyse the sites.
"It does not appear to launch a traditional DDoS attack," said Graham Cluley, senior technology consultant for anti-virus firm Sophos, "and it is not just Google, but AltaVista, Yahoo and Lycos."
"MyDoom uses a revolutionary new technique - I don't think we have seen this before," he added.
The new MyDoom variant searches infected machines for e-mail addresses, like other viruses before it.
But it also uses search engines to look for even more addresses in online forums and webpages.
Google, based in Mountain View, California, announced its plans to float on the stock market in April.
On Monday it announced it hoped its initial public offering (IPO) could raise as much as $3.3bn (£1.8bn), although no date for the IPO has been set.
This would give the California-based firm an initial market capitalisation as high as $36.25bn.
Google's web index is huge, carrying more than six billion items.
The phrase "to google" has entered popular parlance as a verb to describe an internet search.
But it faces growing competition from MSN and Yahoo, which are investing in search technology to try to win back web surfers.