djlen, long story short, I was merely listing specs for your motherboard.
You have a 512MB and a 1GB stick of ram.
If you install both sticks and the system boots up...Great!!

If the system fails to boot, remove 1 stick and boot again.
If the system boots with either 512 or 1GB separately but not both,
there is a compatibility problem.

10 yr old speak:

If the (assume these are cars)512 speed is 20MPH and the 1GB speed is 40MPH,
using these together the speed of both will be 20MPH.
You can't get a slower car to go faster but you can get a faster car to go slower.
Hope this helps.
Good luck.