My Dell laptop with windows 7 just halts after about 1 hour of use with its cursor still working, and when I press the turn-off button it switches to a black screen.
Ctrl+alt+del doesn't work. I have to remove the battery for few seconds to get another 1 hour of use.
How can I find the cause of the problem?
There are a couple of possibilities for this. To diagnose/fix, try some of the following:
1)Download and install the latest driver set from Dell - include the Chipset and Graphics drivers.
2)Try a system restore to a date when you know this was working.
3)Set your laptop power options to not disable your screen
4)Disable screen savers
5)Check windows error logs for a faultering service or process.
Hoep one of these points you in the right direction
Check if the windows is activated. more info here
Unlike Windows XP and Vista, failure to activate Windows 7 leaves you with an annoying, >but somewhat usable system. According to a Microsoft developer blog post on "Microsoft Developer Network," if you don't choose to activate Windows 7 during installation, you will see an "Activate Windows Online Now" message in the system tray. If you don't activate then, you will see and "Activate Now" message every day from day four through day 27. Until day 30, you will get the "Activate Now" message every four hours until day 30. After day 30, you will get the "Activate Now" message every hour, along with a notice that your Windows version is not genuine whenever you launch the Control Panel. In addition, Windows 7 does not perform any system updates after the grace period. Finally, Windows will automatically turn your screen background image to black every hour – even after you change it back to your preference. This behavior continues until you successfully activate Windows 7. More info here What Happens If Windows Is Not Activated?
To confirm activation press
Windows Key+R
then type
slui.exe
if Windows & is activated you should get a window like this
if not, contact Microsoft or manufacturer to activate windows
