A federal court judge has dismissed a lawsuit filed by a Microsoft customer last February, who accused Microsoft of charging her for downgrading Windows Vista operating system to Windows XP on her new PC.

Judge Marsha J. Pechman, of the U. S. District Court for the Western District of Washington, ruled that Emma Alvarado, the complainant, and a resident of Los Angeles, "failed to show that Microsoft violated the Washington Consumer Protection Act's provision for `unjust enrichment'".

The original complaint pertained to all U. S. customers who bought new PCs and paid for downgrades from Vista to XP, and it was later amended to include Windows 7.

Alvarado purchased a new PC from Lenovo in June 2008, which came with Windows Vista Business pre-installed operating system and paid an additional $59.25 to downgrade from Vista to Windows XP. The original filing didn't specify "whether Lenovo or Microsoft levied that fee", but did note that Microsoft reaped "tremendous profits" by charging customers for the downgrade option.

One portion of the filing read, "As the sole licensor of Windows Vista, Microsoft enjoys vast power over OEMs, which it has used and continues to use to stifle competition ... Since the introduction of Vista, Microsoft has effectively eliminated competition in the operating system PC market and created a monopoly position for itself in that market".