You modem, your router, your ISP.
for some reason the modem flakes out on high volume I/O - downloading 3GB ISO or what you are doing. See if you ISP has a support forum or log into the modem and router and check the logs though your DSL or cable provider may be able to see better.
And have your wiring checked.
Might seem easy to blame the OS but I would blame hardware. Been there and upgraded network multiple times - and even OS X versions can impact networks - some but not often there are firmware upgrades for modem or router.
Stuff that worted on XP is not certified for 7 though something supported by Lion would think would also be fine - but one ISP I had did not support my using Windows 8.
First off, thank you for replying.
The only thing that confuses me about that is it doesn't happen when I'm in OSX, also my modem is still running as I have VOIP and it's on. My modem seems fine to me.
I just have to right click on the wireless connection and troubleshoot on Windows 7, and then it fixes itself.