hey im having trouble with my computer. When i switch the power on the computer starts making this long buzzing sound and the fan goes off,  nothing appears on the screen. The monitor is on but it remains black. I have to keep switching it off, removing plug and reinserting it and try to get it working, Tonight it took me four attempts to start my computer! Anyone know the solution to this?LIST computer specs/and operating system........Have Windows xp home edition, pentium 4 processerdid you build this pc? check the wiring on the motherboard.have you changed the psu on it.........and how old is it?1022 MB RAM No didnt build this PC . Its a Dell Dimension 5000. Got it last April so pretty new like.contact dell......>>its still under warranty.....via their website/or phone.i would guess the power supply UNIT has had it....but its a guess!!yeh fortunately still on warranty , thanks for help mateHope dell sort it...........tell them you need a REPLACEMENT unit for your work?......dont let them befuddle you......give you the old acid......it may take a while......put the boot in........you have rights.The long buzzing sound. Is it like an electric crackle or more like a fan buzzing to a stop?

If it is an electric crackle can you smell burning? Can you see if the fans are running properly.

Check to see if the power connecting plugs are pushed fully home. (They should really have retaining clips.)

Either way be careful to avoid electric SHOCK to yourself  or static damage to the computer! Quote

1022 MB RAM

Put the boot in.