Weird corruption problem with http uploads

Question

My brother has a computer running Windows XP with SP2 installed. His computer was behaving badly (very old installation of Win) and one of the problems was that he could not upload jpegs to Facebook, for example. The upload would complete, but the images are garbled.

Finally I decided it was time to format his computer and reinstall windows, which I did.

Still, images would upload garbled to Facebook. I tried using Google Chrome instead of IE, same problem. Then I discovered that this is not just a problem with image uploads, all HTTP uploads seem to fail. For example, I could not send an e-mail with an attachment on his computer using G-mail, the attachment got corrupted.

Any ideas? I don't really know where this problem originates.

1. Happens in different browsers
2. Win XP has been re-installed
3. Just got a new xDSL router (the wired lan section on the old one seized), but same problem

Answer 1

Is it possible his network is glitching? The only correctness check on a HTTP upload is the Content-Length header and even that's option (and frequently unchecked by the receiving end anyway). If his TCP connections are dropping then the receiving end could think it has a full image but really have gotten only the beginning of it.