FDM aka Free Download Manager has malware issues? Seriously? Dude, did you download the real FDM, or some fake FDM from some a fake site?
FDM is a quality freeware which has been around for years now. I have myself been using FDM since many years, without any issues. Here is its site:
http://www.freedownloadmanager.org/
BTW, I still use the old version 3.9.7 of it, since I do not find the new version that good yet. Still, they are constantly updating it.
Look here for more free download managers:
http://www.techsupportalert.com/best-free-download-manager.htm
The article is not yet complete, so look in the list of To Be Reviewed, for more suggestions.
As for downloading videos from webpages, it depends on the way that video has been embedded in to the webpage, depending on which you might have to try some downloaders, like VSO Downloader, Real Downloader, etc. Talking about free ones though, because I use only free software.