SBS2k3 and ISA

Standard install of SBS w/ SQL2K, Dual PIII-800, 1Gb RAM, Mirrored 9.1 C;, D:, E:. worked Great
Exchange Srvr, Outlook, internal mail working on same box
Also Adv-Srvr2K on a single P-III 800, 256M RAM, Mirrored 9.1 C:, D:
And Server 2K on Dual PII-450, 1Gb RAM, Mirrored 4.3 C:, D:, E:
DFS running. DNS, DHCP, TCP, all worked fine
NSLookup fine... ping fine... Could browse LAN, shares, quickly
Internet access via Broadband, Great Speed

"UNTIL" installation of ISA.. on the SBS box..
Initially, very impressive, very fast, as expected... BUT-- less than three hours after install..
Suddenly Dual Processor SBS Box "Maxing-Out", page file @ 100% allowed, logins so slow as to be dead
Firewall Client installs not "staying"... I'm using Roaming Profiles for users with off-line files enabled.

Any Ideas
Have uninstalled ISA.. Now no internet... I've by-passed the SBS box, and am using router for DHCP now.