Hard to answer without knowing more about how far the computer gets upto in the booting system.
(If machine is in warrenty don't mess with take it back)
1. Push ON switch and nothing:- No video,No beeps no lights.
This is either no power to the power supply, the supply is broken or something is loading the supply preventing the supply from powering up.
Solution: Check cables to supply, power source and if fitted fuse and/or voltage selector.
If the supply is being loaded, disconnected hard drives, floppies & CD ROMs and remove all cards except display driver. If still nothing check your supply, if something then switch off and connect each item in turn until failure.
2. Push ON switch and it Beeps (No video). The computer is failing the POST test and is telling you whats wrong depending on the beeps. If there is no video the beeps are probably telling you there is something up with the video card.
Solution: Find out what beeps you got and correct fault. If it is the video card then remove & reseat if still no joy then replace.
3. Computer starts but fails during ram test. One or more of your RAm locations is faulty.
Solution: if you have more than on RAM module (SIMM/DIMM etc) then remove them all bar one then try again, replacing them one at a time until the faulty one is found (then bin it )
4. Computer starts up but shows 'invalid system disk'. This is a problem with boot up sector on the hard drive.
Solution: Try and boot up from a floppy and see if the HDD can be accessed. If so save all you can and then reformat the HDD with the command Format C: /u/s.
5. Computer starts & begins to load windows but load fails.
Wow this is a biggy !. Any number of software / or hardware faults can cause this.
Solution: Just before windows starts to load press F8 then from the menu select Safe Start. If the windows starts then you have a driver/hardware configuration fault. And this too is a biggy to sort with just few lines.
Also try the option to have the bootup logged. Then examine the bootlog.txt file to see which driver/file/app/etc failed to load.
I think if its this sort of problem you'd best email me at
tps72v4@hotmail.com with more info about the problem.
regards
(p.s. this is by no means an exhaustive list of what can go wrong whilst starting the computer (I hadn't even started to mention power supply & processor fan conditioning signals/ CPU core temperature etc)
)