The US government yesterday argued in an 800-page document that Microsoft Corp's anti-trust trial proves the software giant illegally abused monopoly power to thwart competitors. A short time later, Microsoft filed a 450-page submission, repeating its arguments that the government had failed to prove its case. The two proposed "findings of fact" were to be weighed by District Judge Thomas Penfield Jackson as he works towards a final determination of facts in the coming months.