Of course, the very first thing you did when you got your netbook was to create a recovery drive on a USB memory stick wasn't it? That's what you're meant to do (and almost certainly what the instruction manual for your netbook told you to do).
OK, I'd be prepared to bet that you didn't because you regarded it as one of those "I'll get around to it one of these days" jobs, which never actually got done. (The reason why I think that is because I've been meaning to do it myself for years but I've not done it either!)
So, if you're to have any chance of repairing Windows, you'll probably need to buy something like this:
http://www.ebay.co.uk/itm/Windows-7-Recovery-Repair-USB-All-Versions-32-bit-Utillity-Tools-on-a-usb-/201864314848?hash=item2f000cffe0:g:0DoAAOSwnFZXXZ8g
(That's just one example. eBay is packed with similar drives. Some of them are for 32-bit versions of Windows - which is probably what a netbook will be running -some of them are for 64 bit and some cover both versions).
Once you've got hold of a recovery drive USB stick (or remembered where you put the one which you actually did make when you bought your netbook), you'll need to ensure that your netbook is configured to boot from a USB drive first (rather than trying to boot from the corrupted hard drive files first). That will mean going into the BIOS.
There's usually a screen which appears (before Windows starts to load) telling you which key to press in order to access the BIOS. ('Esc' is often the correct one but others are used as well; it depends upon the make and model of your netbook). If there's no such mesage, try googling for the information.
Once you've got into the BIOS you'll need to look for the option to set the boot priorities. (Everything in the BIOS settings is done via the arrow keys, plus 'Enter' and 'Esc'. Your keypad won't work). Once you've ensured that your netbook will examine a USB stick, to look for a boot drive, before it does anything else ,exit the BIOS and close down your netbook. (If necesary, do it by brute force. i.e. unplug the power adapter and remve the battery).
Insert the memory stick into a USB port and power up your netbook. It should then boot from the USB drive and give you access to the recovery options on it. From then on it's trial and error!