When I boot my computer it says that I only have 256mb of RAM. But if I go to Control Panel->Device Manager->General tab, it says that I have 512mb RAM. What could the problem be?

Hope someone can help.

That's odd. I would expect it to be the other way around. You might want to contact the mb manufacturer.

It seem to me that when I first got the PC it did say 512Mb on the boot screen also, but I can't be sure. Have any other ideas?

We need to know what make and model of PC you have. If your PC doesn't have a make and model displayed on it then we need to know the make and model of your motherboard.

We also need to know the make and model of your display card.

My Motherboard is an ABIT Is7-E I865PE 800FSB, I hope that helps.

I should also let you know that my PC is less than a year old and Im running XP.

What display card do you have? When the PC first powers up, you get a message indicating the Vid card and its video RAM before you get the system POST info displayed.

My video card is a Geforce FX 5500 256MB

Then you are probably looking at the readout indicating how much video ram is present, rather than the one showing how much system ram is installed. You wouldn't be the first person to make THAT mistake :D

i've also come across numerous people who've been worried that their video ram has 'gone missing', only to realise that the monitor was badly adjusted, and the 56Mb that they'd come down to had the '2' off-screen :)

Ok thanks, I really hope thats the problem and I will keep it in mind, thanks again.