I've just added more ram to my 512mb set up to take it to 1g but when I check in system information it tells me the total physical memory is 1024mb but the available physical memory is 412.56mb. What does this mean?
If you are certain the memory is properly in place then it sounds like either the memory you got is faulty or its the wrong type of memory you have bought or the motherboard has a limit in the amount of memory it can see and basically it can't see it.
Take out the 512mb as Gandalf says and see what it says without it, then stick the 512 back in and see what it says again, it could just be a bad contact.
Where did you get the memory and are you sure its the right stuff?
I got the memory from Crucial after running their system check. I've just removed the 512 and the total went down by 512. I replaced it and removed a 256 and it went down by 256. The Available figure stayed at 412 each time. According to my manual the motherboard can take 3gs.
I didn't read your ost correctly, appologies. Windows is recognising you have 1 gig so the memory is ok. Ashrich is probably correct in what he says, where exactly does it tell you that theres 412.56mb free because when I look in my PC CONTROL PANEL, SYSTEM it just says 1 gig of RAM. It rings a bell though, it is XP you are using isn't it?