Am trying to use K2 on my home page. av created a menu(HOME) which i have linked to k2 category. am also using an image slideshow (Slideshow CK) on home page.
The problem is, when i click linked k2 category items, the slideshow doesn't hide. i want when i click on linked K2 category items, the articles to open in new page which does not show slideshow

You need to create menu items towards your other categories items as well.
This way the slideshow will not render in these menu items.

If you want the slideshow not to show on items, you can either remove that position from items (either with code or with an extension called Modules Anywhere),
Alternatively you can have multiple categories in your homepage and a menus pointing to a single categories.