Perhaps the Ram Memory module/s, (Stick/s) are not fully seated in the ram memory slot/s.
(Don't know if you have one, or more ram memory modules)
Even if they appear to be seated by a visual inspection, the best method is to remove, and reinstall.
This way you are assured your ram is seated fully.
Before reaching inside your open computer case, disconnect the power to the computer. Unplug from the surge protector, and not from the back of the computer.
I'm sure you know about disconnecting power first, but I have to state this.
Secondly, after the computer is unplugged from power, and the computer case is open; Touch the metal frame of the computer case to relieve your body of Static electricity.
This must be done Before reaching inside the computer.
Perhaps cables have become jarred loose inside, due to moving the computer tower from one location, to another location.
Check to make sure the cables are seated, and tight.
This is HP Support, and the main support page for the Compaq Presario SR1103wm,http://h10025.www1.hp.com/ewfrf/wc/product?product=424182&lc=en&cc=us&dlc=en&submit.y=4&submit.x=7&lang=en&cc=us
In the list under the heading - What type of support do you need, you can click on - Manuals
On the Manuals page scroll down, and click on -
Part Replacement Instructions
This is a PDF file download. Advise letting the file download all the way, before looking through it.
With this manual you will have instructions, and illustrations for guidance to making sure the cables are tight. It shows the various cables.
The manual also shows how to replace ram memory. This way you will have instructions for removing, and reinstalling your ram memory.
Going back to the main suport page, you can click on - Product information, and will have access to an illustration, and photo of your motherboard.
On the Product information page click on -
On this page click on -
Motherboard Specifications MS-6577 Giovani, Giovani2
Scroll midway down the page for the motherboard illustration, and photo.
Makes it more clearer as to where the power cables, and interface cables go, as shown in the Parts Replacement Instructions manual
(Interface cables. In this case, the flat ribbon cables that go from the motherboard to the Harddrive, CD/DVD optical drives, and if there is one installed, the Floppy Drive)
If none of the above makes any sense to you, please state so in a Comment, and I'll walk you through it step, by step.
The above solution is in reference that you have just disconnected all peripherals, (Mouse, Keyboard, Monitor, etc), and have physically moved the computer system, from one location to another.
It can also be used for information if your have removed hardware components, or added hardware components to your computer, and may have missed connecting a cable.
If reseating the ram memory, and ensuring all cables are connected tightly, does not 'cure' the problem, perhaps the wires from the Front Panel to the motherboard have come loose.
(Front Panel is where the Power On button is)
There is no manual to give you for this. If this is the problem let me know in a Comment, and I will go out to my shop, and get you this information.
I have a Compaq Presario SR1103wm out there)
If the wire connectors from the Front Panel to the motherboard, (Connector on the motherboard is a Front Panel header), is Not the problem, then I suggest it is a problem with the Power Supply.
Power Supply has a weak voltage power rail. Enough power to light light's, and maybe spin fans, but not enough power to turn the Processor on.
1) ALL the lights use less than 1 Watt of power
2) EACH fan when operating can use 2 to 3 Watts
3) A typical Processor uses 55 to 125 Watts when operating at maximum capability.
Depends on what Processor it is, as to how much wattage it uses.
There is a way to test the power supply, or you can replace it with a know, good, compatible power supply for a test.
Should I have misunderstood your problem, please come back, and state so in a Comment.