Windows 7 - Hi-jack Registration Key

My son had something happen on his PC. His background went black but icons, task bar, etc were still showing and a message box came up to ask him to verify his registration. He's had Windows 7 for about 5 months now and it was activated when it was installed. I wasn't home at the time to see the screen but he typed his registration number. This seemed like strange behavior.

Is it possible some software was hi-jacking his registration number to be used on some pirated windows 7 disk?

The next day his PC booted properly and then he uninstalled software called DIVX. After it rebooted his PC no longer worked. It doesn't even load. It goes pass POST and then a dark screen and then stops. It doesn't shut off.

I'm trying to determine if it was the registration or the DIVX that may have caused the problem.

Where did the Win 7 come from? Was it a retail version?
Also fill in the system specs.

DIVX itself should not have had anything to do with the validation issue. Though uninstalling any type of codec software carries a chance of it messing up an install unfortuantely :/

For Windows 7 using "Sharky's" codec pack or installing the VLC player are the safest bets for stable video of almost any kind imaginable on Windows 7.

For now doing a Repair Install from the WIndows 7 install disk may be the best bet for getting the computer back on line. It'll reinstall windows and al the drivers. Existing programs and user data will remain.

Right. Its all about where he got it. If it was pirated in the 1st place....then microsoft must have downloaded the ungenuine update to his PC and its no longer genuine. Things that happen when u download this update:

Background goes black

Get a constant Windows message saying you Windows is not gENUINE

A water mark that stays in the bottom right hand corner i believe

Win 7 Home Premium was bought from newegg as an OEM. This is not an upgrade but a full version. It was installed on a brand new harddrive.

When the PC boots and ends up in a black screen he gets NO message about the OS not being genuine. Booting in windows safe mode ends up with the same black screen. He has 2 GB RAM.

I seem to have 3 options. his registration key may have gotten deactivated some how (unlikely or he would have gotten some message to that affect, I think). 2) The DIVX uninstall did something wrong or 3) some hardware problem with his mobo.

I will have to wait until tomorrow and see if I can reload windows from his CD. Too late to do it tonight.

This can happen to legal copies sometimes but I have my suspensions.

Were there any hardware changes recently ?

No hardware changes at all and no message saying the OS is not genuine. In fact no message at all.