Over the past few months I often find some web pages will be very slow to load (45 seconds) and when they do load, they have lost all formatting (text is left justified, sometimes over writing itself). Since this started I have had my ISP change me from DSL to cable (with the requisite change in modem and in increase in download speed from 6mb to 25mb) with no change to the problem. When I get this problem I can usually refresh and get the web page properly formatted. The problem occurs at random. It does not seem to be related to any particular web sites (that I have been able to discern). It is also not confined to a single PC. It might be related to firefox as that is the browser usually (but not always) in use. It happens on many web sites, but not all the time. Both wired and wireless PC's get the problem.
There is a firewall / router and a switch, either of which could be part of the problem.
Running windows 7; firefox 8.0.1; IE 9.0.8112; Cisco RV-042 firewall/router