How old is the computer? What is the brand and model of computer or motherboard? How old is the hard drive.
This error can be caused by a lot of problems including driver failure of any of a number of components, memory module failure, power supply failure on one rail, CPU fan failure, or corrupt Windows install.
But the likely cause is a failed hard drive.
First test is to see if it will boot in SAFE MODE. Cold boot your computer by pressing the on button, then immediately tap the <F8> key once per second until you get the notice that it is booting in Safe Mode.
If it will fully boot in Safe Mode, then perhaps it is not the hard drive, and you can look for a video graphics port error which could be a hardware or driver failure.
Then to get out of Safe Mode, try
Start->Run-> sfc /scannow
My guess is that the hard drive is failing. The floppy drive is churning, and probably the optical drive as well, because Windows is seeking a boot device. This can mean that part of the hard drive boot sectors (First 8 sectors) are bad and cannot be repaired. Time to get a new hard drive.
The fact that you see the beginnings of a Windows boot means you have a 67% chance of rescuing your data using this old hard drive in a USB enclosure after you load windows onto the new drive... then dragging an dropping the old data, or using a recovery program.
Get back to us with brand and model and we will attempt to be more helpful.
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