Just a footnote to this, I've found internet browsing to be a pain in win 7. My router is super busy, as though the system were conducting an enormous download I could neither see nor control. Thus, it would take minutes to open a webpage as something is munching all the bandwidth.
Anyway, in the course of a disk cleanup, I noticed something like 40gb of error reports, ran tcp view and sure enough, windows is generating, saving & uploading error reports constantly. I disbaled error reporting & hey presto, back to normal.
A quick google around the place & it's cropping up a lot. MS are aware it seems & I don't think I'm the only one to see the irony in error reporting causing errors!