Possible Virus?

My MacBook Pro was purchased in early 2012. It has been ruiming slow in general, but last week I recieved the error message below. I turend of my computer and restanten, but I continue getting this error message whenever connecting via Safari. Any tips? Is there any reason to believe calling this nummer is a good idea? This message isn't even proper English!

"http://computer-security-alert.com

There is a .net frame work file missing due to some harmful virus

Debug malware error 895-system 32.exe failure.

Please contact system technichians to rectify the issue. Please do not open internet browser for your security issue to avoid data corruption on your registry of your operating system. Please contact computer technichians at

Tollfree Helpline at 1-866-403-7963"