Technical Support

Did I understand correctly that the computer had 256MB and 1GB memory modules installed? If so, it is strongly not recommended to install modules with different amounts of memory on the same computer (there are exceptions, but they only apply to advanced motherboards, such as the Asus P5Q Pro). 256MB is unlikely to provide any additional performance compared to 1GB, so it is better to leave the 1GB module as is.
P.S.: but you can also reinstall the operating system if you are concerned.