Tuesdays

Hi, What is it about Tuesdays?? Every Tuesday afternoon for the past 4 weeks my computer has played up. I can be on the computer in the morning and everything is fine, but as soon as I go on in the afternoon the flippin thing plays up. I reboot but can I get back on the internet with my broadband connection??? Can I heck as like. So......... every Tuesday afternoon if I want to use my computer for the internet I have to use the old fashioned dial up connection grrrrrr