Changing from xp to vista?

hi all for a while now ive had a genuine copy ov windows vista basic but only ever loaded it once and that was on my old pc as there were more negative reviews about upgrading from xp than good ,ive now aquired a new pc and again am considering upgrading but this time am more weary than ever as my question is last time i upgraded everything was done correct and vista had loaded and replaced xp i also noticed vista had compressed xp and the programs i had into a file program called windows old (this included programs like(ccleaner ,nero,glary utilities )get ma drift the thing is most ov these i eventual downloaded again but this time for vista id also download avast anti virus system for vista too so eventually i slowly deleted certain contents from the old xp file although not all as some ov my old software you could only get or use with xp so it would only work by opening up that old file what my main concern is i now have a computer upstair and now have a wireless router leading to my questions if i upgrade to vista will i have to set up wireless again or will it still work at all ,is there anything i need to do before i even upgrade ,im not so worried about out else program wise just a bit worried about it effecting the wireless set up sorry its a bit long winded but im not that computer wise