Hanging Computer, HELP !

Ever since installing an Actiontec DSL Gateway I've got this problem where my PC will hang when I double-click on My Computer, or sometimes when I try to "save image as", or whatever seems to call on one of my two hardrives. I'm forced to ctrl+alt+delete and restart every time. It does'nt happen every time I click a button or whatever but, it does happen at least once every day. I think it has something to do with the DSL gateway because when I disconnect the ethernet cable, the computer never hangs. I've been troubleshooting this for a few months and would really appreciate any suggestions.
Dell Dimension L800r
Windows ME