all posts in a category won’t show

In my blog OnlyinSilence.com, there are 17 posts under the category ‘the life of an ordinary earthling’. But when you click on it, it will only show 10 posts and I can’t see a ‘previous entries’ link at the bottom. How can I fix this? Kindly tell me the step by step instruction as I am not so versed with all the codes.

I’m using WP2.3.3 and Aspire Theme, if this helps. Thank you ;o)