windows 7 shutdown while downloading

Hi I have recently been trying to download anti virus and spyware on to my computer and as soon as I click on download it will close the window and shutdown my computer. Is there anything that I can do to stop this and so I can get the software on??

 

What software are you trying to download & from where ?

Are you currently using any antivirus software ?

 

Is the same thing happening when you download other items or only AV and Spyware.

 

I've tried to many to really tell you all of them, I just thought it was the software itself. But the website I have tried the most from is majorgeeks.com. I was using the free trial Norton AV that came on the computer, it had expired so I uninstalled it to see if it was causeing the problem. But other than that I haven't tried anything.

Its also happened once before with something else besides AV and Spyware.