Maybe its not hardware related, I live in Costa Rica, and ISP's here are a real pain... some actually did throttle internet speeds for video streaming, rendering them un-usable.
You can tell me i'm paranoid but test it...
Glasnost: Test if your ISP is shaping your traffic
Have you tried using a third party uninstalling tool to remove flash? Then re-downloading and re-installing it?
Java could also be related (not really sure).
Any noisy firewalls that could cause it?
It's all that I could think, i'm not as experienced as some of the guys around here, I hope some of it helps!
Good luck!