I bought a used CPU with a Celeron 1.0 and XP Pro. The seller put a 4g hd in place of the orig. I have a 13g hd and I want to use the 13g as the master and use the 4g as a slave with the OS. The 13g is clean with a new format. Is this possible? I have ran two hd's in the past, but the master has always had the OS. When I have tried this one that way (4g as master) it gets full of stuff from temps, antivirus, and firewall programs. This really seems to slow it down. Any help?