My bet is that you are experiencing interference on your wireless connection. Perhaps one of your neighbors recently installed a wireless router. You might try changing your wireless channel (in your router settings) from its current setting to channel 1, 6, or 11. There are lots of things in the 2.4 GHz band including cordless telephones and microwave ovens.
You inspired me, Pianoman! -- M82A1A
Pianoman, you have inspired me. -- hefe
Pianoman, that's not very inspiring. -- edhara