After a week or so of working fine, my display goes black. Power button light is still blue and on. When I try to re-boot, DVD Burner green light goes on as if spinning up, goes off, then computer does nothing. If I disconnect power cord for a week or so, and then try to boot, computer does the same thing. If I then press the power button which is lite blue, it will proceed to boot. Have run PC Doctor when computer is working, everything checks out fine except DVD burner will not read or write DVD's, only CD's. When I took out CMOS battery for a few hours and replaced it with a new one, it booted up, worked for 5 days, then went to black screen with power button on colored blue.

Your waiting for a long time before plugging in the power again etc. has no advantage over waiting for the minimum time. A Cmos battery normally lasts for about 5 years - if your computer isn't that old, it's extremely unlikely there's anything wrong with it.

Failing power supplies are common and can cause your symptoms. Ssometimes in the early stages of failure the power supply partially works, yet it will not allow the computer to fully boot.
Check your PS.
See response 4 in this:
http://www.computing.net/hardware/w...
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"...everything checks out fine except DVD burner will not read or write DVD's, only CD's. "

I'm assuming you have one optical drive - a
DVD combo drive (reads and burns both CDs and DVDs).

- a DVD combo drive will not be detected properly if it is running in PIO mode - it will not be detected as a burner drive, and may not be detected as a DVD reader either.
Check which mode it is running in:
http://www.microsoft.com/whdc/devic...
If it is in PIO mode, try resetting it to dma if available, then going back in to see if it is then in a mode other than PIO.

- if this DVD combo drive has been used a lot, the DVD laser may be dirty - try using a laser lens cleaning CD in it
- if that doesn't help, DVD combo drives have at least two lasers and it's not unheard of for one to malfunction.
- if your DVD combo drive is IDE connected and capable of 16X DVD +R or DVD -R or higher, it requires an 80 wire data cable in order for it to be able to operate at it's full rated speed, and it may not be detected properly if connected to a 40 wire data cable.

Less likely

- you must have the drivers for your mboard main chipset loaded in order for all of your hard and optical drives to run at their full rated speeds. If you still have the brand name software installation on this computer those drivers are already there, but if you have re-loaded Windows using a regular Windows CD, you must install the drivers for the mboard, particularly the main chipset drivers, after Setup has finished so that Windows has the proper drivers for and info about the mboard, including it's IDE and SATA drive controllers.

- boot up problems can also be caused by poor connection problem in your ram slots. See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
http://www.computing.net/hardware/w...