Fireofox 3 has a built in feature of scanning for viruses after each download is completed.That could slow the process specially if the file is big.That can really take some important time.So if you want to disable this automatic virus scan you just have to follow these simple steps.Yeah yeah the same old about:config trick.Here you go.
- Type about:config in the Firefox address bar
- Now filter the following browser.download.manager.scanWhenDone
- Preference should be : No
- Set the parameter to False