How do I change my desktop's bios?

I want to change ram size of my computer, because I am going to upgrade my ram. But when I turn on to the bios screen, I chose the boot setup,and you cannot change the ram size, it said read only. so how can i go in bios to change it, my computer is DELL dimension e310How do I change my desktop's bios?
Perhaps you need to rephrase the question? ... Usually when you install the RAM the BIOS will adjust automatically to the update. There is very few reasons for you to change anything in the BIOS.How do I change my desktop's bios?
u change ram size by physically adding more .. if it doesnt detect then it may be already to the max supported ..
you cant change the ram in the bios setup window. it detects it automatically. just buy the ram that goes along with your computer and when you turn it back on ,after you install it, it will tell you the current ram that you have

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