downloads won't open from the Download List:

Tis2web Free Download

If you need assistance within the US or Canada please contact 1-800-825-5886 prompt #3. In Australia use 0011-1-800-825-5886 prompt #3. We offer cracked GM Tech2win software for GM MDI tech3 interface, you can get the activation tech2win software without license limitation. Cracked GM Tech2win software for GM MDI software activation when you install tech2win software, and try to update or run tech2win software, your license has expired on GM MDI tech2win software, show.

The Downloads Manager ('Ctrl+J') is more like a log of downloads, it does not verify that the download still exits. Make sure you are setup to download to a permanent location, not into temporary files that get cleaned by the browser or by CCCleaner or something designed to clear out temporary files.

Tools > Options > General > Downloads: ...

Tools > Options > Privacy > [x] Remember download history

Don't clear your download history automatically, but having a lot there whether they exist or not, can slow down Firefox at least it was an issue:

Tis2web Free Download

http://img232.imageshack.us/img232/4928/clearcachew.png

Tis2web Download Torrents

The may be additional about:config settings in addition to the above.