Computer shuts down by itself - Dell Inspiron 537s PC Desktop

Im having a problem with my dell inspiron 537s it wasnt powering up unless i unpluged the power cord for a day then i could get it to power up but then it would have an alert about the booting file then it would shut down if i shut it down a few times by shutting it off by then power button it would come up now it doesnt come up any more any suggestions

There can be many reasons of unexpected shut down of your system.Below are some remedies to solve it

1
Run an anti-spy ware and anti-virus utility to make sure that the shutdowns aren't being caused by a malicious program. If the shutdowns are infrequent, install a CPU temperature monitor utility to keep track of the CPU's temperature. If the CPU is overheating, or the shutdowns are frequent, then you will need to troubleshoot your computer's internal components.

2
Check any recently installed internal components to ensure that they are properly connected to the computer's motherboard. Make sure any new expansion cards or memory modules are securely seated in their slots, and ensure that the power and data cables are properly connected to any new drives.

3
Check for large dust buildups on your CPU fan. If the fan isn't effectively cooling your CPU, the overheating CPU will cause your computer to power off. Carefully pick away large pieces of dust with your fingers, and then spray the CPU fan with a can of compressed air to remove the rest of the dust.

4
Reapply the heat sink compound between the CPU and heat sink if the computer continues to turn off unexpectedly. Heat sink compound is a pasty substance that fills the space between the heat sink and processor, which increases the heat sink's ability to absorb heat from the CPU. But worn heat sink compound won't properly redirect heat away from the CPU. Power down your computer, disconnect its power cables and open the case. Unplug the CPU fan's power cable from the motherboard, remove the heat sink and fan combination from the CPU, and then apply the heat sink compound to the CPU--refer to your product manuals for details on reapplying heat sink compound.

Thanks .
Have a great day.