Whenever I try to download a file from the internet, it does not work. It will act like it is downloading the file, but then when I go to the download history in Firefox, it shows the file but if I right click on it, it does not give me the option to open or open the containing folder or anything. The options are grayed out.
Click the Firefox button, then Help then Restart with Add-ons disabled. See if you can download now. If yes then an Add-on is causing the problem. Use Firefox / Add-ons to disable them a few at a time until you find the culprit.
Have you tried downloading files through other browsers?
For example IE or Google Chrome?
I use Google Chrome and it seems faster than the rest and less faulty.
Here's something you could try:
1. Uninstall the firefox
2. Go to C:\Documents and Settings\yourusername\Application Data\Mozilla
3. Delete everything there, you may have to reboot because some files may be locked by Firefox before deleting
4. Reinstall firefox
That would normally work. But you will need to add in all your plugins and addons again.