Windows keeps uninstalling when updating windows

Hi Everybody,

a couple of months ago i bought parallels for Mac.
The next thing I did was buy Windows 7.
And here comes my problem:
After having installed Windows successfully on my mac, windows offers me to update something and download an antivirus.
Every time I do this, Windows just uninstalls itself, so that i have to start all over again.
Does anybody know how to solve this problem?
Why does Windows uninstall itself every time I try to download an antivirus and update some windows-programs?

Thanks for your help
Julen

 

There is no mechanism in Windows to uninstall itself, so when you say it's uninstalling it's probably something else happening which is not uninstalling Windows.
When you say that 'windows' offers to download an antivirus that's where I get suspicious, because that sounds like malware, a fake antivirus.

Screenshots might shed some light into this.