pc memory upgrade!

[ih]

hi
i need to upgrade memory for my niece.She currently has pc with 4 slots and currently has 2x512mb i don't know the speed but crucial confirms as DDR PC2-5200. According to the motherboard manual the pc can handle max 8192mb .The correct memory is DDR2 800mhz/667mhz /533mhz . I was going to install pair of (2x1GB800mhz DDR2 crucial make which are sold as paired kit.
my concern is the pc will have 1024 mb i donot know the speed and the upgrade 2GB with 800mhz speed are they compatible with each other or will i find problems. As she stays some distance from me am not in a position to open the cover and look and donot want to waste 2x512 mb.Thanking in advance for all the help and advice.
ih edit please note i have been since informed that the 1024 (2x512mb are 533mhz so the final concern is can i add 2x1GB 800mhz thanking all

 

[Stivino]

If she downloads Belarc Advisor, it'll tell her everything she needs to know about her system.
http://www.belarc.com/free_download.html
I think PC5200 is DDR 667 and PC6400 is DDR 800

 

[opps]

I just phone mr.memory in brighton and let them tell me what suits my set up. Good prices and great support and service.

Just give them the model number or mobo if it is a self build.

http://www.mrmemory.co.uk/


BTW the following is far better than belarc

http://www.gtopala.com/download/siw.exe

It will even tell you the age of the ram, internet passwords and info you thought you never wanted to know