I have a Hp slimline with windows xp 2006. It flashes all the time. The first thing I did was run a scan with my Mcaffey. No viruses. I haven't uploaded anything lately. Noone else uses my PC I haven't even been letting Zach use it now for a couple of weeks or more. He uses the laptop instead. HP updates automatically. My service is through my phone acct. I have had it for 3 years and never had this problem before. I have DSL.