855-912-6201

Had a "scareware" message pop up on my computer with this number.  Basically, my web browser (Google Chrome) locked up, and there were several messages stating that I needed to call this number... which is supposedly Microsoft... and they will help fix the problem.  Not doing so could result in "complete data loss".  This is obviously not a Microsoft number, and not a real message from Microsoft.  My anti-malware software (malwarebytes) found the issue & fixed it automatically.  Definitely do NOT call the number on your screen if you get this message.

I have had the same problem repeatedly on Google Chrome (as stated by Roger above) I always end up shutting down the computer because it will not allow you to exit Google or do anything unless you respond, which I will not do. As if I don't have enough to deal with from the constant onslaught of lowlifes calling on the phone constantly. WTF, with all the technology available, these scumbags always find a way in.

I just had the same problem, also using Google Chrome :(

I had this exact same thing happen with me in Chrome in the super early morning hours (maybe 3am?) on October 22, 2015.

I disconnected from the internet (not very tech savvy so I wasn't sure if this would help), then closed Chrome via Task Manager. I then ran a full system scan with Norton over night still disconnected from the internet, but it didn't find anything (ie total security risks detected = 0).

The actual text of the message was the following (I took screenshots):
------------------------------------------
this first line was a header thing for the little light grey window
"The page at 1619779932.rsc.cdn77.org says:

Your system has detected possible Suspicious Activity. Please call the toll-free number below for a Microsoft-Certified technician to help you resolve the issue:

1-855-912-6201.

For your safety, please do not open internet browser to avoid data corruption to the registry of you operating system.

Please contact  support at the toll-free Helpline 1-855-912-6201

PLEASE TO NOT SHUT DOWN OR RESTART THE COMPUTER, DOING THAT MAY LEAD TO DATA LOSS AND POSSIBLE  FAILURE OF THE OPERATING SYSTEM, AND POTENTIAL NON BOOTABLE SITUATION RESULTING IN COMPLETE DATA LOSS. CONTACT MICROSOFT CERTIFIED TECHNICIANS TO RESOLVE THE ISSUE CALLING TOLL FREE - 1-855-912-6201

Tollfree Helpline: 1-855-912-6201

Your system has detected possible Suspicious Activity. Please call the toll-free number below for a Microsoft-Certified technician to help you resolve the issue:

1-855-912-6201.

For your safety, please do not open internet browser to avoid data corruption to the registry of you operating system.

Please contact  support at the toll-free Helpline 1-855-912-6201

PLEASE TO NOT SHUT DOWN OR RESTART THE COMPUTER, DOING THAT MAY LEAD TO DATA LOSS AND POSSIBLE  FAILURE OF THE OPERATING SYSTEM, AND POTENTIAL NON BOOTABLE SITUATION RESULTING IN COMPLETE DATA LOSS. CONTACT MICROSOFT CERTIFIED TECHNICIANS TO RESOLVE THE ISSUE CALLING TOLL FREE - 1-855-912-6201

Tollfree Helpline: 1-855-912-6201

Your system has detected possible Suspicious Activity. Please call the toll-free number below for a Mic...CHNICIANS TO RESOLVE THE ISSUE CALLING TOLL FREE - 1-855-912-6201
1-855-912-6201.

Tollfree Helpline: 1-855-912-6201

Your system has detected possible Suspicious Activity. Please call the toll-free number below for a Microsoft-Certified technician to help you resolve the issue:

1-855-912-6201.

For your safety, please do not open internet browser to avoid data corruption to the registry of you operating system.

Please contact  support at the toll-free Helpline 1-855-912-6201

PLEASE TO NOT SHUT DOWN OR RESTART THE COMPUTER, DOING THAT MAY LEAD TO DATA LOSS AND POSSIBLE  FAILURE OF THE OPERATING SYSTEM, AND POTENTIAL NON BOOTABLE SITUATION RESULTING IN COMPLETE DATA LOSS. CONTACT MICROSOFT CERTIFIED TECHNICIANS TO RESOLVE THE ISSUE CALLING TOLL FREE - 1-855-912-6201

Tollfree Helpline: 1-855-912-6201

Your system has detected possible Suspicious Activity. Please call the toll-free number below for a Microsoft-Certified technician to help you resolve the issue:

1-855-912-6201.

For your safety, please do not open internet browser to avoid data corruption to the registry of you operating system.

Please contact  support at the toll-free Helpline 1-855-912-6201

PLEASE TO NOT SHUT DOWN OR RESTART THE COMPUTER, DOING THAT MAY LEAD TO DATA LOSS AND POSSIBLE  FAILURE OF THE OPERATING SYSTEM, AND POTENTIAL NON BOOTABLE SITUATION RESULTING IN COMPLETE DATA LOSS. CONTACT MICROSOFT CERTIFIED TECHNICIANS TO RESOLVE THE ISSUE CALLING TOLL FREE - 1-855-912-6201

Tollfree Helpline: 1-855-912-6201

---------------------------------------------------

Yes, it repeated itself a few times and even seemed to blend itself somewhere in the middle-ish.

I've not turned off my computer since this happened, nor have I shut the lid to make it take a nap (it's a laptop). I'm not really sure what to do since Norton didn't find it...

I feel I should also mention that I've not reconnected to the internet since (I'm typing this up on a different computer). The only other programs I've opened since are MS Paint, MS Word, MS Excel, Windows Explorer, and obviously Norton (I only had Chrome open at the time). Also, I doubt it's relevant, but just in case, my laptop runs on Windows 7.