Help! How do I get the windows Disk spyware off my computer!?

I have this virus on my computer. I keep deleting it off of my desktop and restarting it but it keeps reappearing. It is called "windows disk" it is a fake security alert that tries to make me purchase a program. I ran My Mcafee nd Norton Virus protection. It still is there. There is also something called Windows security alert that pops up every few seconds on my screen. Any computer experts out thee who can help me please????