Motherboards usually have three or four slots in which you can put a single stick or DIMM of memory.You can get them at 4 GB each now so in theory you could have 16 gb of memory if you were so inclined.In the future they'll probably have even larger DIMMs.
It depends on the motherboard. If you can find out what type of motherboard you have, you can look up what type of memory and how much of it you can install into the memory banks. Keep in mind that the operating system that you have may limit how much of the installed memory you can actually use.
depends on the motherboard, but average would be 4gb.
More often it is the motherboard which determines the Memory which can be in a PC.
DDR or SDRAM
yes it is possible to use DDR800 on DDR667 motherboard. But to be certain please check you motherboard spec.
Windows XP doesn't directly determine what type of memory can be used; it depends on the motherboard. If the motherboard is compatible with Windows XP and the motherboard supports this memory module, then you can use it with Windows XP.
The Compaq Presario come with 128 Megabyte of memory. The motherboard has up to 1 Gigabyte capicity of memory space. If you want to upgrade your memory, you can use a RAM Stick.
What memory your motherboard can use will depend entirely on your motherboard. There is no way for someone to answer a generic question like this.I can add a personal note that I did upgrade my dad's laptop to contain one 1GB stick as well as the 512MB it came with. Of course, I have no idea what motherboard it has (or even what manufacturer it is).
cpu
Chipset and CPU define the type of memory.
yes, you can use the motherboard with another Processor and add the ram on it and everything else
sure; CPU used to memory for processing data. it use mother board cache memory and it also use ram memory.