Same problem here but with Windows XP and ZoneAlarm Security Suite v8.0.298.035. This was a known problem with 8.0.020 but I thought they would have fixed this by now.

Does update five or six times per day and when this happens everything stops. More generally applications very slow to load but once loaded are OK until the next antivirus update.

In 2006 I ditched Norton Internet Protection because it was bloatware and took over my PC completely. ZoneAlarm was a great improvement then but I fear it is going down the same road as Norton. It is getting so bad that I am looking for an alternative product.