How computer infected by Backdoor.Doublepulsar?
Backdoor.Doublepulsar is generally coming from the social engineering. The spam email attachment plays a vital role to spread this trojan on your PC. The other distribution methods are also included like a drive by download, spam links, and fraud advertisements. Although the payload can be anything, various advance forms act as backdoor that contain a controller, which may have unauthorized access to the infected computer. In such case the attacker steal the user’s data like banking information, passwords, or IP address (personal identity).

Symptoms of Backdoor.Doublepulsar?
Desktop popups: there are various kinds of pop-ups and messages display on the desktop like advertising things or say that your PC in infected and requires protection.
Slow computer: if you are looking that your computer is randomly started to slow down during the minor task, this may be the symptoms of infection of the Backdoor. Doublepulsar.
Applications won’t start: sometime another application program is run by its own, but not as per your requirement that you want. this may be another type of trouble and may be the vulnerability case.
Browser popups: the browser popup is another type of sign for the infection of your computer. You may face multiple advertisement moment when you start browsing the internet. This may lead to a trojan infection.

http://www.fixinfectedpc.com/uninstall-backdoor-doublepulsar-computer-removal-guide

I found a patch from Microsoft.

It may have come from the NSA?

DoublePulsar is a backdoor implant tool developed by the U.S. National Security Agency's (NSA) Equation Group that was leaked by The Shadow Brokers in early 2017.[1] The tool was able to infect more than 200,000 Microsoft Windows computers in only a few weeks,[2][3][1][4][5] and was used alongside EternalBlue in the 2017 WannaCry ransomware attack.[6][7][8]

Sean Dillon is a senior analyst of security company RiskSense Inc. who first dissected and inspected DoublePulsar.[9][10] He said that the NSA exploits are "10 times worse" than the Heartbleed security bug, and use DoublePulsar as the primary payload. DoublePulsar runs in kernel mode which grants hackers a high level of control over the computer system.[3] Once installed, it has 3 commands: ping, kill, and exec, the latter of which can be used to load malware onto the system.[9]

https://en.wikipedia.org/wiki/DoublePulsar

Way to go, dickheads.

Anyway, it is a bad one from what I read. They have full control of your computer. There was a NYTimes article about it last week.

It was like every program was downloading twice. It slowed down videos a lot

The patch from Microsoft seemed to have worked, at least for now.