Android Tablet OS Upgrade?

Ok so my mom just bought an Android based tablet about a year ago, it has a slightly modified version of Android 4.04 (Ice Cream Sandwich) loaded on it, and the other problem is, it has a bunch of manufacturer bulls**t apps preloaded on to it, most of them are either fake, or nonworking, and its really annoying. What I want to do is download a fresh copy of Android 4.04 (presumably from their website) and install it on to the tablet and start from a fresh copy of Android 4.04. The problem is, even though I am very tech savvy, I have never worked with the Android OS before, therefore, I am a bit worried that I will just end up bricking my moms tablet. So my question is, Where and how would I obtain a (GENUINE AND LEGAL) copy of Android 4.04 for a tablet, and do a clean installation of it on the tablet. There is nothing my mom wants that is already on the tablet, so it’s ok if it needs to be completely wiped. Please be as detailed as possible, I really don’t want this blowing up in my face. Thanks in advance guys! (ps, it’s an Ematic EXLB3B tablet, Just let me know if any more info is needed!) (pps, and if it can’t be done, just let me know)

thank you
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