# Norton Antivirus virus - nau.exe is sucking my CPU percentage **URL:** \ **Category:** Factual Questions\ **Created:** [May 20, 2011, 2:12am UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530 "2011-05-20T02:12:39Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Uncle\_Brother\_Walker](https://avatars.discourse-cdn.com/v4/letter/u/f08c70/32.png) [@Uncle\_Brother\_Walker](https://boards.straightdope.com/u/Uncle_Brother_Walker)\ **Post date:** [May 20, 2011, 2:12am UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530/1 "2011-05-20T02:12:39Z")
Here’s the story: Earlier today, I noticed my CPU percentage was at 100% because my computer was being slow. Granted, I had more than 5 internet explorer windows open, but that’s not uncommon. EVERYTHING had slowed to a crawl. Even shutting down windows to free up stuff didn’t work and was slow as molasses. I looked at my task manager to find out what was going on and there’s a new program running. nau.exe. And it won’t let me stop the process. The old “Access is Forbidden” error window pops up. A google search led me to many websites which basically boiled down to 2 basic positions. Yes, it is a virus and it is tough to remove, but you can do it by downloading (my website’s) antivirus software (sometimes more than one tool) and it will kill it that way. The other position is that Norton Antivirus installs that because it is their Norton Antivirus update (hence the NAU name) which needs to run and keeps your software updated. I don’t believe this, because I’ve used Norton for years and never noticed this file. A hard drive search cannot find this file on my computer. Spybot didn’t find it. Norton didn’t find it either. Snopes had nothing on this topic at all. This guy is pretty sneaky. So what’s the deal? Is this a legit Norton AV file, or should I download all the generic website’s software (and risk more infection) to delete this or am I worried about nothing? Thanks in advance for any info y’all can provide. ---
**Author:** ![Markxxx](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@Markxxx](https://boards.straightdope.com/u/Markxxx)\ **Post date:** [May 20, 2011, 4:51am UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530/2 "2011-05-20T04:51:56Z")
Here’s some article from the [Norton Website](http://community.norton.com/t5/Norton-Internet-Security-Norton/Ver-18-5-0-125-auto-downloaded-and-wants-to-install/m-p/356294/highlight/true#M142058) What is [nau.exe](http://us.norton.com/support/kb/web_view.jsp?wv_type=public_web&ssfromlink=true&sprt_cid=9b82789f-b2f2-44b9-be05-ea13207c18d6&seg=hho&ct=us&lg=en&docurl=20091216104440EN) Seems to be legit, but you’ll have to read them through to see ---
**Author:** ![bardos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bardos/32/1069_2.png) [@bardos](https://boards.straightdope.com/u/bardos)\ **Post date:** [May 20, 2011, 6:55am UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530/3 "2011-05-20T06:55:12Z")
My advice is to use a different anti-virus program. Norton acts like a virus itself. Totally slows down your computer. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [May 20, 2011, 2:46pm UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530/4 "2011-05-20T14:46:15Z")
If you uninstall Norton, be sure to do a system restore, as Norton is notorious for screwing things up when uninstalled. The 2011 edition is supposed to not have this problem, but I still wouldn’t take any chances. But I think it’s likely that nau.exe has been infected or corrupted, as there’s no way it should be stealing CPU cycles. In fact, it may not be actually doing it, and you have a nasty malware infection lying to you. Download this [antivirus CD](http://www.avira.com/en/support-download-avira-antivir-rescue-system), burn it, and reboot your computer with the CD in the drive. If your computer says something about pressing a key “boot options,” press that and choose the CD. If Windows winds up starting up anyways, you’ll have to look in your BIOS and make sure that your CD drive is the primary boot device ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 20, 2011, 3:20pm UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530/5 "2011-05-20T15:20:57Z")
As others have mentioned Norton is a monster in and of itself. It does what it says on the box fine but you pay for that in a number of ways including noticeably diminished system performance. Up to you but I’d recommend a different antivirus suite (some here are fond of free offerings but for the pay offerings I have had good luck with [Kaspersky](http://usa.kaspersky.com/)). ---
**Author:** ![Uncle\_Brother\_Walker](https://avatars.discourse-cdn.com/v4/letter/u/f08c70/32.png) [@Uncle\_Brother\_Walker](https://boards.straightdope.com/u/Uncle_Brother_Walker)\ **Post date:** [May 20, 2011, 8:54pm UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530/6 "2011-05-20T20:54:47Z")
Wow. Looks like I’ve got some reading to do. Thanks, everybody! ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [May 21, 2011, 5:21am UTC](https://boards.straightdope.com/t/norton-antivirus-virus-nau-exe-is-sucking-my-cpu-percentage/582530/7 "2011-05-21T05:21:19Z")
You use Norton. You use Internet Explorer (5 windows even!) And you wonder why your machine is slow?