Windows 7 64, Slow, Inconsistent Internet Access?

(In summary - cant get the download speeds I am expecting on my new computer - and sometimes cant get connected to the Internet at all)I am having trouble browsing the internet - but the trouble is the "symptoms" keep changing. So its very hard for me to diagnose the problem.Basically - my browsing (download) speed varies from 0.5 mbps to 8 mbps and sometimes will cut out all together for prolonged periods. Typically it stays at about 2mbps. I am used to having a steady 8 mbps. I thought it might be an issue with my ISP - so I set up another computer next to my new one and ran speed tests simultaneously (one right after the other). The old computer was consistently getting ok results whilst my new one was not - so I think its unlikely to be an ISP issue. There were no other computers on the network at the time.

I thought it might be hardware related (it is a new computer) so I ran one of those linux live discs on my new machine - and again got good results - whilst when I returned to windows - I get poor speeds again. So this leads me to think it is not a hardware or a wireless network issue. (Linux wasnt running as much stuff as win 7 was). What is especially frustrating is sometimes it works fine on windows and sometimes it doesnt - and there doesnt seem to be any obvious cause. Also since it keeps fluctuating its very hard to tell if what you do is fixing it - or if its just naturally reverted back to normal. Further - sometimes I can be getting half my normal expected speed (4 mbps) but as I dont use that much bandwidth I wont notice until it drops below 2.nd in what may be a completely different issue sometimes I will get zero downloads speed (but wireless strength remains high) - if I go to system config and type "netsh int ip reset resetlog.txt" this "seems" to fix this issue - but not the slow speed issueIts my first win 7 computer.

Its a samsung RV511 with Windows 7 home premium (64 bit edition) Norton security preinstalled. I have installed chrome and 3ds max. I have installed all the windows updates and all my hardware drivers are up to date. I am connecting to the internet through a wireless router. I set it up initially as a home network - tried changing settings to "work" didnt seem to do anything.