Unless you happen to have a cheap 3rd party dongle, use 2.4GHz wifi, and have to have internet access while doing your presentation or whatever. (3rd party dong

Unless you happen to have a cheap 3rd party dongle, use 2.4GHz wifi, and have to have internet access while doing your presentation or whatever. (3rd party dongles often have bad shielding and it interferes with 2.4GHz signal, it's a pretty widespread issue. You cannot really "fight it," though, you need to get another dongle.)