First, what type of computer is it? acer, asus, dell, something else?
Second, What crap did it come with? mcafee, free version of office you now have to buy, stuff like that?
Download CCleaner 3.13.1600 - FileHippo.com
This is what I use typically to remove the crap. Its relatively straight forward. Once you install it go to tools and the first thing that comes up should be an un-installer. Just go through the list and remove what you want. Although I do want to point out, if you have a net book, some of the things on that list are actually beneficial or required for performance, so don't just go crazy deleting everything your not familiar with. after your done un-installing everything, there is a registry tab/icon above tools. if you clik on that and then scan it will find all the "dead" items in your registry, things like pointers for old programs you may have un-installed, pointers for older versions of programs that now have new ones, etc... Stuff your computer doesn't need any more, but your computer still reads. taking time and space.
If you have any specific questions, PM me. I get an e-mail notification almost instantly, although I can't garuntee a quick response.