I just installed Commerce Kickstart 7.x-2.9 and I'm having trouble with the parameters embeded on the links.

On the home page of the default demo site, which should have pictures of t-shirts and so on, I can only see the pictures for the <img> links where the paths do not contain any ?= style parameter.

For example:
The logo is shown --> <img src="http://localhost/commercekickstart/profiles/commerce_kickstart/themes/co......
But the slideshow is not --> <img src="http://localhost/commercekickstart/?q=sites/default/files/styles/hp_slid......

Also, whenever I click on any link I end up seeing the directory file list on my browser.
Some links work if I manually add the index.php text between before the ?= symbols.

I'm pretty sure this has something to do with my Apache or .htaccess configuration but I cannot find where the issue is.

Sorry if this is a really stupid question, but I've really tried for a while to search the web for answers and I cannot find the solution. I guess I'm not asking the right questions, that's why I decided to post the explanation here to see if somebody can help me out.

Thanks in advance.