I somehow managed to download one of those "free download accelerator" programs, and it didn't show up as a program to uninstall (under control panel). So, I did a search on the file, and deleted it. This was obviously a bad idea, because now my computer will not download anything. I think somewhere I have it set to use the accelerator to download things, because it still shows up as an option when I right-click on things. "Save target as" also won't work.