Activation 'de-activates' months later

Hi,

I bought a used Dell Vostro PC with Windows 7 Pro last November which after 3 months of working fine started to show' activation needed' warnings. As the machine had some bloatware I decided to do a fresh re-install of Windows 7 Pro with my system disk last Feb. All proceeded well although I had to activate by phone.

Then yesterday for the first time since re-installation, I'm suddenly getting a warning notice that W7 needs to be activated again. On looking at System it shows I'm not activated. But, when I reboot then System shows I am activated with a genuine Microsoft badge. I've scanned for viruses with MSE and Malwarebytes, but nothing showed up. One thing I noticed was that all my Restore points had been wiped out when this problem began yesterday. When I booted up today I checked my activation which was good, until an hour ago when again I got a message that I was not activated which was confirmed on System and that I needed to activate by today. I rebooted and once again I'm 'activated'. Please note I haven't changed any hardware since I bought the PC.

I phoned Microsoft who confirmed my product key was genuine but couldn't explain why I was having this issue. I have got 2 separate images of my system to use when I wasn't having activation trouble, but I'd be grateful if someone could perhaps enlighten me as to why this activation problem is occurring.

Hello Layback Bear and thanks for your welcome.

Yes, I see KB971033 as installed. I've had no further issues since I last posted. I'm waiting to see what, if anything happens today, Saturday as the expiration for activation time would have passed.

Unfortunately when I open up the diagnostic tool log all I get is the event viewer and not the diagnostic report as shown in your example.