Computer Ram not working together?

I might be able to help. I have pc100 and 133 sticks and currently have 1GB of RAM installed, seems like a lot for as old as the size is. Anyways try using the default setting in bios and see if that changes anything. When I added RAM Windows just ran the same as it did before, but usally sometimes computers notice that the hardware has changed and give you the option to continue using your computer that way. What might work is taking the extra RAM stick out. Backing up all of needed files and then shut the computer down and put the extra RAM in and reintall Windows or you can use a bootdisk and see if that can byp the error message. Sorry if none of this works, never had this happen to me before. Usually when I answer a question, I use the knowledge from my experiences.