I need hellp!!!!

Sigh! Does anybody know how to reformat a laptop? Its soo weird. I can't open task manager, when i open a file, it closes itself.. i can't upload any files, i can't transfer stuff, can't do so many simple simple things! sighh!! Its a Dell laptop, i've checked the site but support is only available for those under warranty which mine has expired. So i don't really know what to do. The site doesn't even show their nearest support centre or in fact, any centre at all!!! How stupid!!! Pls pls pls let me know if you have any solutions! :)