Hi,

http://www.crucial.com/uk/store/list...t=Go+to+Step+2

That link will allow you to check what memory his PC will take. There is also a diagnostic tool.

And:

http://www.belarc.com/free_download.html

A system diagnostic tool that will tell you what computer it is, and has a link to the Crucial site.

As the machine is so old, I think that you had better make sure that it supports 256Mb strips