|- list your system specs. You need at least 1GB RAM for a decent performing XP system.|
- list the name of the anti-virus/anti-malware program you're using. Bloatware such as Norton, McAfee, TrendMicro, etc should be avoided. There are plenty of lightweight freebies available (AVG, AVAST, Microsoft Security Essentials) that work just as well & won't bog down the system.
Is "media test failure" the entire message or is there more to it? like PXE-E61: Media test failure, check cable ? That message has to do with booting off a network. If you don't need it, disable it in the BIOS.
Did you install all the latest drivers (chipset, video, audio, network, wireless, etc) after the reinstall of Windows? Have you run Windows Update & installed all the critical updates? There's probably several optional updates that would be useful as well.