is there a good Internet security guard for my Pentium 3 PC
What is it you are looking for specifically, Firewall, Antivirus, Anti Malware ?
How much RAM is installed ?
Pentium III only clocks up to 1gHz, I believe, so comparitively, is rather slow, and if
you don't have max ram for your system, Installing Complete Security Suites could
bog your system down dramatically.