I have a Dell Inspiron 530 destop running Vista Home Premium. I have a Dell wireless mouse and keyboard which share the same USB dongle and they have started to switch off after about 20 minutes inactivity. The only way to switch them back on is to unpluge the dongle and reinsert it. It doesn't matter what USB socket I use - all the other bits plugged in (printer,webcam,external hard drive)still work. If I plug in a spare Microsoft wireless mouse it doesn't go to sleep; and if I connect the offending keyboard and mouse into my laptop they continue to work forevever. I'm stumped. Can you please help? Thanks.