Use of Self-Signed Certificate Authority

I have generated a self signed CA.
Can I use the same SS-CA to "sign" all other certificates ?
e.g. CA & Client certs that I will export to windows 7 clients ?
server certificates for use on my rhel 7.0 VPN server ?
I'm using an rsa key type with a length of 2048 bits.
Will they all use the same private/public key set. ?

Guy