Dropping packets

I am trying to troubleshoot a problem on my home network. I have an SMC 2804WBR router. I have a new Dell C521 wired to the router and an older Sony VAIO as well. I have a HP pavilion ze4300 that communicates to the router wirelessly. I also bought a Dell Wireless printer with the C521. I am having problems with dropped packets on my two desktops. I have swapped out cables, and it still seems to have problems. My laptop is fine. I recently got the Cox Digital Telephone. I am wondering if this is causing a problem? Wierd thing is my laptop doesn't have problems. Only those that are hardwired to the router. How do I troubleshoot this to see if it is my router, cables, Cable Modem, etc.? I am just trying to isolate it right now using ping and moving cables around. I don't see much of anything in terms of tools that I can use to help. Thanks!

Bill

If the laptop's fine, it's likely a problem with the PCs. To test the modem, run it directly to each computer. Start by updating the Lan drivers and running the Network Connection Wizzard on each PC. Check in Hardware Manager to make sure you don't have any conflicts, i.e., red or yellow warnings. If this doesn't work, I'd start from scratch setting up the network. Reset the router to it's factory settings, usually there is a button on the back to do this, this will delete any log on names or passwords you set and they will revert to the factory settings. Recycle the modem. Disconnect everything. Follow the set up directions that came with your router.