IPhone :: Syncing To Itunes From A New Computer Without Having Original Itunes Library?

i am stuck in a tricky situation and would things first i know this is quite a frequently asked question as i have done a bit of searching on the net about it however could not not find anything that totaly matches myproblem, i have recently purchased a brand new laptop which runs windows 7 compared to my old desktop which ran XP, i have tried syncing all of my iphone 4s contents onto my new laptop's itunes library including everything not just music or videos and i got the infamous pop up "The iphone is synced with another Itunes library. Do you want to erase this iphone and sync with this Itunes library" the problem is that my original itunes library does not exist no more as my desktop was completly wiped and had XP redownloaded onto it again because it had a virus, which also wiped all of my hard drive so i cant even get everything i backed up off of my phone from it, i have managed to sign in to the itunes store and allowed my laptop to work with itunes,i have also transferred my purchases from my phone to my new itunes library but this only includes my apps and obviously not my contacts and photos and everything, i still get the pop up if i go to sync my apps from my library anyway, is there any way i can delete my original itunes library without it even existing anymore so that i can just start afresh and sync everything i have on my phone now directly to my new itunes library? or do i need to purchase this iphone rip/backup/store software that everyone goes on about or something? to be honest its really annoying my now as i just want to be able to sync everything like how i used to,

Info:
iPhone 4S, iOS 5.1