is there a dowloadable software so i can bypass a proxy server in an windows XP OS?

Yes, go to :
www.yoproxy.com
or
www.proxyrat.com
or
campusfreedom.info

But note that your administrator can detect that someone is using such sites if he has the right tools. I am an administrator myself and I catch many users every day loool
so if you work in a company then you might get fired for bypassing the company’s policy.

CHeers

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