Setting up two database on oracle

I am using Oracle Database 10g Express Edition on windows.

I want to install two database instance on one system. Both the开发者_运维知识库 instance will have similar db structure but are of different version and at one time I'll be using only one instance.

Can anybody help me how can I achive this?

Thanks!

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It is not possible to install multiple instances on Express Edition. http://download.oracle.com/docs/cd/B25329_01/doc/install.102/b25143/toc.htm#BEIEJGGF