If you use onboard graphics:
Remove all peripherals (Cards, Connectors, RAMs etc) from the mother board and screw-out the motherboard from the Cabinet. remove processor-fan, processor and battery from the motherboard in the sequence written here. Keep the motherboard on a well-moist (not dripping-wet) towel over-night. Dry-up the motherboard next day and put processor, processor-fan, RAMs and monitor. Connect power supply and short the pins on Motherboard to switch on.
If you use esternal graphics card:
Remove graphics-card from the mother board alongwith all peropherals (Cards, Connectors, RAMs etc) and screw-out motherboard from the Cabinet. Remove processor-fan, processor and battery from the motherboard in the sequence written here. Keep the motherboard on a well-moist (not dripping-wet) towel over-night. Dry-up the motherboard next day and put processor, processor-fan, RAMs and monitor. Connect power supply and short the pins on Motherboard to switch on.

Have u check ur memory?... ur videocard and powersupply...thats the main problem of pc if it has no display....just try it one by one...hope it can help u