HP Compaq dx2300 Desktop PC?http://h20000.www2.hp.com/bizsupport/TechSupport/Home.jsp?lang=en&cc=us&prodTypeId=12454&prodSeriesId=3352967&lang=en&cc=us
90 percent of desktop computer failure, cab be attributed to;
A) The computer is dirty inside, to include the Power Supply.
B) The Power Supply is bad
Suggest you start with cleaning the inside of the computer out, but suspect the real problem is the Power Supply.
Because the CD-ROM is not working.
Your Power Supply converts your household/business AC electricity, into 3 low main DC Voltages.
Depending on your country;
USA = 120 Volts AC
Europe = 220 Volts AC
Australia = 220 Volts AC
Japan = 100 Volts AC
This is converted into 3 low DC Voltages for the computer;
A) 3.3 Volts (DC)
B) 5 Volts (DC)
C) 12 Volts DC
Each of the above is a voltage power rail.
The amperage for each power rail is stated on a label, on the Power Supply.
Voltage times Amperage = Wattage
Again, Voltage x Amperage = Wattage
All of the amperage of the voltage power rails are combined, (Added together), to equal the maximum Wattage, the Power Supply will deliver.
This should be stated on the Power Supply label also.
A) IF, all of the LED lights were on at once, they would use less than 1 Watt of power.
B) EACH fan uses 2 to 3 Watts of power.
C) A typical Processor can use 51 to 125 Watts of power.
[ Intel Pentium Dual Core E2160? Can use up to 65 Watts,http://en.wikipedia.org/wiki/List_of_Intel_Pentium_Dual-Core_microprocessors#.22Allendale.22.2C_.22Conroe.22_.2865_nm.29
You press the Power On button. This in turn presses against a Power On switch,http://www.directron.com/atxswitch.html
This in turn, activates the Soft Power On feature of the Power Supply, and turns it on.
The first chipset to receive power is the BIOS chipset.
The BIOS program looks to see what devices are connected, does a Ram Memory count, turns the Processor on, then hands the computer over to the Operating System.
[ Windows XP and Windows 7, are two examples of an O/S ]
Your Power Supply provides enough power to turn the Processor on, then falls to it's knees. Doesn't have enough power to keep the Processor on.
[ A typical CD/DVD drive requires 15 Watts of power. It isn't there when all of the other hardware needs power first ]
Suggest you find a Power Supply that is KNOWN to be good, and COMPATIBLE, for a test unit.
Or you can test the 3 main voltage's coming out of the Power Supply, with a Multimeter set to DC Voltage.
Or you can just replace the Power Supply.
I would prefer you test with another unit, or test the voltages, before you spend your hard earned money.
It's up to you.
Diagnose the problem first. I could be wrong with the above, but if you diagnose using a test unit, or test the voltages, we will know whether the Power Supply is the problem.
Always start with the power First.
Perhaps there is an unused computer you may have access to, and can borrow it's Power Supply for a test unit. Has to be KNOWN to be good, and has to be COMPATIBLE.
What is Compatible? Means it has to have at least the minimum power cables, and the Power Supply must fit in the computer case.
(It is an ATX power supply)
Need recommendations for a Power Supply, post in a Comment.
Also will step by step guide you in replacing.