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The court also ruled in the summary judgement that Microsoft would not be liable for indirect infringement of the patent, according to a filing at the US District Court for the Southern District of California.

The decision is the latest in a larger group of patent cases Alcatel-Lucent has taken against the companies. Microsoft has said it would appeal a digital music patent case after a jury told it in February to pay Alcatel-Lucent $1.52 billion (£787 million).

The summary judgement, filed Thursday, related

Many hand-held organisers and mobile phones let users navigate through menus or dial a number by tapping a stylus onto the device's screen.

It is part of a group of four patent cases, related to user interface technology, scheduled to go to trial in May.

Alcatel-Lucent spokeswoman Joan Campion said the court still plans go ahead with a patent trial related to tablet computers, which use a stylus to control computer functions.

The court has thrown out two other patent claims tied to the case including one related to Web coding technology and is expected to rule on a fourth patent in April, Microsoft said.

A Dell representative said the company's policy was to decline comment on pending litigation.

Alcatel-Lucent shares closed up 26 cents, or about 2 percent, at $12.12 on the New York Stock Exchange. Microsoft stock slid 29 cents, or more than 1 percent, to $27.32 on Nasdaq, where Dell fell 4 cents, or 0.2 percent, to $22.26.