Can't download .exe, stuck at 99% for all browsers

I would suggest using lftp. You will get better diagnostic messages. However, lftp itself must be downloaded first, e.g. as a part of cygwin or from the above mentioned link (not an exe file!). That archive must be unpacked into some directory where lftp can be executed. Cygwin version includes lftpget:

lftpget -c http://example.com/JavaSetup7u21.exe

Bare-bones lftp command is a bit less obvious:

lftp.exe  --help
lftp.exe  -c get http://example.com/JavaSetup7u21.exe

To answer your non-question

The Opera browser was playing similar tricks on me as in your case, aborting downloads. That was probably due to poorly configured or poorly working router that dropped packets. Lftp has superior reconnection abilities and would still download the files completely.

Temporarily disable your Anti-virus or/and Anti-malware programs