Turn PC on, screen comes on for a few seconds then goes off.

try to replace a video card

did it work before? how long since its like this
how was the situation on pc since last used "before getting as its now"

have you tried this monitor with another system?

is the problem from when pc is first turned on? i.e do you see anything at all?

 if monitor works with other system try as janezz note and try another card in it.

Hello there,

Have you recently installed new video drivers for your computer? If you have you might want to roll back your drivers. Does the screen go black if you boot into safe mode? Try booting to the advance boot menu and try a last known good configuration. Also, this was mentioned already but try a different monitor.

Keep us updated

When does it go blank? Right before window loads?

The screen goes blank before the windows screen displays so I would have thought that would eliminate a driver issue ill try ram, video card and different monitor with a friend later...

Thanks

Aura

Also,

press F8 when booting up and see if it lets you get as far as where you can choose to boot up in Safe Mode.  if you can, try to boot to Safe Mode.  If that doesn't work, please try booting with your "Last Known Good Configuration".  If that setting works, it was a driver issue.

Your motherboard has gone

Does the PC appear to continue booting?  Could be our old friend - bad capacitors on mobo.

so you actually see pc post then and then goes blank befor the win load sreen, are you sure its not as windows loads? if you enter bios does it still go blank.

I think its a bit early to say motherboard is dead without testing all other issues first but indeed as willcomp noted you can check for bad caps.

Well i think it was an unusual problem.

Ok

The post screen displays then the monitor goes off

First I changed the AGP card

Then tried a pci graphics card

still no luck

removed one of the sticks of ram and places the second one is slot one

Still no different

The i put the ram from slot one into slot two and now it works!

Now this could still have been one of two things

The ram reseating or perhaps dirt lodged in the ram slots

But as ram was the problem or linked to the problem I have awarded the points accordingly

thanks a lot for all the feedback it is always highly appreciated

Aura