How do I install my RAM in my laptop? (Read Description)?

I already put it in my computer, but it's telling me that it can't use it... the default is 2GB, and i have 4GB installed... is there some BIOS setting i need to change.. or what? (A screen shot of my SYS INFO: a href="http://i499.photobucket.com/albums/rr352/KaleXD/Sysinfo.png)" rel="nofollow"http://i499.photobucket.com/albums/rr352…/a As you can see, it thinks my installed RAM is 4GB, but my total RAM is 2GB... please help...