Pull out the new memory module. If the system operates normally after that, the issue might be because of mis-matched RAM or memory that is incompatible with the mainboard. In addition, the memory timing settings could be set incorrectly in the BIOS. It's also possible with an older system that updating the BIOS could solve certain issues when adding extra memory.
How much memory is in the system in total ... first, without the new module, and then after installing the extra RAM? If you are installing more than 512MB, you'll need to edit the system.ini file for Windows to work properly.
<A HREF="http://www.anandtech.com/guides/viewfaq.html?i=27" target="_new">What is the maximum amount of RAM for Windows?</A>
My preferred memory testing utility: <A HREF="http://www.memtest86.com/" target="_new">Memtest 86</A>.
Toey
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