|Win XP is set by default to automatically reboot when it encounters an unrecoverable error.|
To have XP possibly display an error message you can investigate instead of the computer rebooting:
1. Click Start, and then right-click My Computer.
2. Click Properties.
3. Click the Advanced tab, and then click Settings under Startup and Recovery.
4. Under System failure, click on the small box beside Automatically restart to remove the checkmark.
5. Click OK, and then click OK.
If you then get an error message, look at all of it's details.
"My pc restarting and I got a message saying that windows has updated and installed an important security software and this required an automatically restart. How do you turn this off?"
Why would you want to turn it off? Either you installed software just before that, or some program did that automatically - that's a perfectly normal message. I've have never, ever heard of malware doing that.
- Some anti-malware programs auto-update themselves in the background - sometimes they need to reboot the computer after something has been installed (e.g. AVG 8.x sometimes does that), but in that case, it almost always tells you it wants to reboot - and requires an answer from you - it doesn't normally do that automatically. However, sometimes the window it pops up is behind another window. If you don't notice the message and you reboot the computer, or if some event reboots the computer, you may get a message while booting that says the Windows settings have been updated, or similar.
- Windows Automatic Update may do that, depending on what settings it is set to.
Those Event Viewer messages are relatively useless info without you quoting which Source and Event error number they had in the Event Viewer
The links you supplied don't work because they have a dot at the end of them, and even when the dot is removed, they don't point to a specific error.
The second one looks like the one you get for Userenv - 1517.
That's a common error everyone gets, and you can ignore it, unless you are getting major delays when you Shut Down Windows.
If you scroll down the Applications list you will see that error happens frequently - just another XP bug.
The other errors are about an ATI software file, and a setting for ATI software.
Did you recently install ATI software, or updated ATI display drivers? Windows Automatic Update does not do that.
I DO NOT recommend you use the device drivers found by using the Microsoft Update web page and a Custom search.
The first error - there may be a problem reading that ATI file - it may be damaged.
The third error, the second ATI error - ati2mtag
CRT invalid display type.
RIGHT click on a blank part of your desktop screen, choose Properties (goes to Display Properties) - Settings
What does it say your monitor type is?
Do you have a CRT or an LCD monitor connected?