Guess I didn't give quite enough information. The iMac in question is the primary printing station in a networked graphics environment. It talks to three network printers and the Internet via Airport, and to a pair of local printers and a scanner via USB. The Airport base station is an older model 802.11B unit. It serves as the gateway to an Ethernet network with a pair of routers serving two HP PostScript laser printers (one color, one B/W), a G4 PowerMac, a Windows 2000 workstation, a Canon ImageRunner and a T-1 Internet connection. Also communicating with the base station wirelessly are another G4 PowerMac desktop and a PowerBook G4. The PowerMac desktop has several hard drives, one of which is the master repository for client files from all the other computers. Files are archived by transferring over the network. The iMac is loaded to the gills with USB connections: through direct connections and a USB hub, it talks to an HP scanner, an HP large- format inkjet printer, an Epson medium-format inkjet printer, a USB wireless adapter, a multi-format camera card reader, keyboard, mouse and a USB flash memory stick for sneakernet file transfer. The iMac is restarted every day. I installed Tiger Cache Cleaner on it recently; this sped it up a little. It also runs Norton AntiVirus. Hmm... that's a lot of info I left out! From Michael's response, I infer that any of the USB devices could be a problem; guess I'll start there. I've never looked at a log in Console.app -- but I'll research how to do that. TIA for any further thoughts. Ralph Jones