After the computer has been on for awhile, the screen does this jumpy horizontal lines flickering thing. Usually if we turn of the computer or put it in sleep mode and then restart it after awhile it will be o.k. for awhile, and then it starts flickering again. What's up and how can I fix it?

SOURCE: Dell XPS420 Freezes after being in sleep mode

Is there a reason why you cant turn off sleep mode and just let the screen saver kick in? You can do this by right clicking on your desktop and goto properties. Then ScreenSaver, then click on power.
Change these values to never and then go back and set your screen saver...

Hope this Helps...
Joe
DataMiner

SOURCE: Monitor keep going into "sleep" mode

try to reseat the memory modules and restart the computer and computer boots to normal mode/then go to power options in control panel and disable the sleep mode option for the hard disk

SOURCE: Computer goes to sleep before it even starts up

Hi there, it appears as though the Power Options are set too short a time and the PC is going into sleep mode. Go to Start menu/Control Panel and look for Power options. Set them all to "never" This will prevent her PC from going into sleep mode. Good Luck.

SOURCE: sleep mode problem

hey , first go to same mode in ur PC by pressing F7 .
thenblue window will appear so there select normal mode . thus ur PC will never go to sleep mode.

SOURCE: I have a dell dimension

Plug the monitor into another computer to determine if the monitor is damaged or working properly. You can also plug another monitor into your computer to determine the same thing.