Hello, I have a dell Dimension 9150 that will not boot. The #1 #3 Diagnostic lights are alternately flashing, and the #4 is solid, all the while the lan light is clicking and blinking in between #1 and #3's dance. Not sure if the lan blinking plays any part in the diagnosis but... I have 4 X 512mb sticks of ram that came from the factory with the machine. I have taken turns with each of them to identify a damaged module, cleared cmos, reseated graphics card, cpu, and ram modules. Changed power supplies, removed the front USB panel and jumpered the ribbon cable start the machine (to test for damaged usb ports) I have looked in the rear for damaged ports and everything seems to look ok. I don't know where else to go from here. Any help is greatly appreciated.
What is the reading of the power button LED, solid green, blinking green, solid amber, blinking amber?
Are there any 'Beeps'?
The 9150 Troubleshooter and Diagnostic Guide is HERE
<ADMIN NOTE: Broken link has been removed from this post by Dell>
Did you try the using following procedure, to check the memory modules?
Remove all the memory modules, then install only one module in slot 1, then see if the system boots and if the computer starts normally, reinstall an additional module.
Does not boot, move the module to slot 2 and again see if the system boots, no boot, try the module in slot 3, no boot, try installing in slot 4.
Still does not boot, then remove the first module and using the second one, repeat the sequence described above.
Still no boot, try installing any remaining modules, one at a time, using the above procedure.
Continue until you have identified a faulty module [or slot] or reinstalled all modules without error.
Still does not boot, buy a new compatible memory module and try that.
Then if the computer still does not start, it's possible that the motherboard has failed and needs to be replaced.