Psystar has been given the official go-ahead for its revised countersuit against Apple, following the news last year that saw Psystar's initial counter-claims dismissed.

The Mac clone maker changed its angle from accusing Apple of breaking antitrust laws, to claiming the company "stretches copyright laws".

A judge has approved the changes and hinted that if Psystar proves its allegations, it could mean that other companies could sell PCs with Mac OS X pre-installed.

Psystar has to officially submit its altered counter-claims in a week, after which Apple must respond within 20 days with the trial scheduled to begin on 9 November.

"Both sides should be taking discovery and preparing themselves for trial and/or summary judgement", the Federal judge said.