Hmm. The worst that ever happened to me along those lines was one of them complained "unknown publisher" - but it installed fine & clearly was by Dell.
(1) Are you sure you were set for Win 10 drivers at the site, & did you click "view details" & see it did mention Win 10 as in my picture?
(2) How did you reinstall your previous version of Dell Update?
Dell Update shows version 1.7.1015.0 in your earlier picture of Programs & Features (P&F), but I only see 1.8.1114.0 & 1.7.1007.0 available at your site.
(3) What version shows up in P&F now?
(4) When you boot your computer now, does the Dell Update icon show up in your Tray (right side of Taskbar), & does it state it is checking for updates & declare you are up-to-date?
Depending on your answer to these questions, we might decide to let things alone regarding Dell Update. I've sworn I won't take it back into this computer, not even just to see what happens. I know you are Win 10 version 1511, because update 3135173 shows up in your Installed Updates. I am still Win 10 build 10240. But I don't know whether that is making a difference.
Update 3/9/16: OK, I tried to download it from my own site, & got...
...So, I clicked "delete", & it was not downloaded. I guess we need to forget that one. Or, contact Dell. You're computer is new enough not to incur a charge.
Edit 3/9/16 9:26 PM: To be accurate, the download did occur. After clicking "delete", it ended up in the Recycle Bin.