I have (2) 256 MB PC100 Non ECC SDRAM DIMM chips (cards) which work wonderfully in HP and Windows 98 now. My HP has a slot for another card but if Windows will only take 512, I guess I won't be using the third slot. Not going to spend more money to find out it won't work. Tried the 128 MB in last card place but no go. And, don't ask me to give up Windows 98. I have Windows XP Home edition on my Gateway Laptop and not thrilled with it. Probably because I need to read my manual and get used to it (LOL). I updated my Gateway to 512 MB by buying one of their 256 MB cards and it worked super. Say what you will about Gateway but they sure make it easy for a non-techie like me to upgrade things in a Laptop. I am now doing a lot of graphics using PaintShop Pro and the reason I wanted to upgrade this computer. Program doesn't shut down unexpectedly now when I create large size paintings. Judith <snip> exactly how many sticks of RAM do you have and what are their sizes? your mainboard may not recognise a stick of 512MB... also, the higher MB chip *usually* needs to go in the slot that is closest to the processor. ~s To unsub or change your email settings: //www.freelists.org/webpage/pctechtalk To access our Archives: http://groups.yahoo.com/group/PCTechTalk/messages/ //www.freelists.org/archives/pctechtalk/ For more info: //www.freelists.org/cgi-bin/list?list_id=pctechtalk