There is no one size fits all when it comes to computer security. We can make suggestions, you can install a program, then find out the program makes your computer run even slower.
You just have to find one that plays nice with your system.
For a firewall, Comodo has a free version for Windows 2000. The reason I know this is because when I installed Comodo on my new computer last month, Comodo interface was different than it was on my other computer. Yesterday I did some checking and searching-found out I had installed Comodo for 2000 AND XP instead of the version for XP and Vista. I now have the XP/Vista version. http://www.personalfirewall.comodo.com/dow...d_firewall.html
Click the Version 2.4 (for Win 2000 users) tab.
edited to correct a spelling typo
Edited by Queen-Evie, 26 August 2008 - 09:39 AM.