I have this problem with my wireless internet, it only happens on 1 pc and all the other ones are perfect.
Basically what happens is the internet will work absolutely fine for weeks and weeks but then suddenly it will slow to a crawl.
It persists being incredibly slow and will never return to normal, it is not slow in safe mode or (this part I don't understand at all) when I uninstall my GFX driver. The only thing I found that restores it's normal functionality for a while is (this part also makes absolutely no sense to me) unplugging my HDD, plugging in another one I have and then plugging back in the original. Things that I have have ruled out include, virus, heat, services on start up (I eliminated all possibilities), my graphics card. Doesn't matter which HDD I use, the problem will arise again on either one eventually. Also I don't think it's my ISP because the internet works fine on all other machines. Any thoughts or suggestions on the matter would be very much appreciated.
also switching around graphics cards seems to work, i have to take the installed one out, then put in the new one which does not make internet work normally. Only when I reinsert the original does the internet operate normally again. This is ridiculous and I have never heard of a similar problem on any forum ever. Just happens 2 me. Sweet!