If you get a page where some images/thumbnails are missing, and you refresh the page, are the same images still missing? or if you get a page where the formatting is missing and you refresh does that correct it (some, if not all of the time)?
Have you tried running a ping to see if your internet connection if going up and down?
Using the win7 or xp machine, go to the ‘Run…’ (XP) or ‘Search…’ (Win7) line on the start menu, type CMD, press OK/enter and then when the command prompt box appears type:
ping google.com -t
you should get….
Pinging google.com [74.125.230.148] with 32 bytes of data:
Reply from 74.125.230.148: bytes=32 time=15ms TTL=52
Reply from 74.125.230.148: bytes=32 time=17ms TTL=52
Reply from 74.125.230.148: bytes=32 time=17ms TTL=52
Reply from 74.125.230.148: bytes=32 time=16ms TTL=52
Any line where you get ‘Response timed out’ are potentially your line dropping, enough of this or prolonged periods and you’ll start getting issues surfing.