Financial and security experts estimate that it will cost $3.2 billion to replace the technology destroyed at securities firms affected in the Sept. 11 World Trade Center terrorist attacks. TowerGroup experts say that of the $3.2 billion, $1.7 billion will be spent on hardware—trading stations, sales stations, workstations, PCs, servers, printers, mini-computers, storage devices, cabling, communications hubs, routers, switches and the like. The other $1.5 billion will cover the services and software needed to install