jaisy, Hello & to BC Forums!
I'll try to assist, hopefully your computer can run long enough to go through the Setup again & also that your Data is secure elsewhere. You can download the Setup again, and can even create the ISO to re-install your Windows 8 computer fresh, but you'll need to be on that computer for this to work. So that Microsoft can verify the key w/out you needing to input a COA (same during install).
You have two options, downloading the Setup file and letting Windows 8 upgrade to preserve your documents & Data, or creating an ISO for clean install. Some users has reported that Windows 8.1 ISO's now will 'see' the Windows 8 COA during the Setup phase & install it cleanly, I have the ISO & DVD, but have not actually performed the install yet. Because I have a key for a software that I purchased (Malwarebytes Pro Lifetime) missing. It's around here in my rat's nest or years of accumulated computer software, but have yet to find it, it's likely under my nose & don't see it.
Anyway, off to the races shall we go!
Go to this page to begin, where you'll download a small Setup file. This detects what type of key you have internally.
Once you run that, you'll be offered the opportunity, unless it's recently changed, to download either a Windows 8 or 8.1 ISO for creating media now by DVD or Flash drive, or by saving as an ISO file to a folder in a hard drive (preferably external) so that you'll have it for whenever needed. What's important is that if offered a selection, be sure to download the version you have. For example, don't download a 8 or 8.1 Pro ISO when it's the base version. Do not download a K or N version, unless these applies to your area. Check your license to see what you have.
I see you just added a post, it could have been your needed drivers were in there, plus all of those required for GPT partitioning. Patience is of high virtue when posting for assistance on these forums. We're not paid, on demand support, so some members may require days before getting an answer. Deleting all of those partitions has in essence, knocked you out of options, other than returning the computer or purchasing recovery media set (lowest cost option). This will be what came with your computer, including all bloatware & what I suggest to do, unless you'd rather pay for ASUS staff to do the same at a higher price.
Warranty doesn't cover OS corruption, hardware only.
I do suggest when your computer is returned, be sure to create a recovery DVD set, as well as a backup drive to create system images on a regular basis (monthly at a minimum) to get you out of jams like you got into. There are several Free & paid backup software options to consider & I cannot live w/out my backups.
Backups are just as important as running security software. You really need to get into the practice of this to prevent future errors of this type. as well as create that Recovery Media set, which will consist of 3 to 5 DVD's.
And next time, please give us a little longer before pulling the trigger. You could have saved some big bucks using the link above.
Good Luck with the outcome.
Edited by cat1092, 16 March 2015 - 11:30 PM.