Error 0xc000000f : Boot failed after I accidentally changed my C drive to active

I was trying to hard reset my computer.

I was removing a parallel installation of Ubuntu which was installed alongside Windows. To remove Grub, I deleted the Ubuntu partition and then used the recovery drive (a drive within my computer) to hard reset using BIOS. Its a feature in HP laptops.

Everything was installed nice and fine but I went to my C drive partition (which had Windows installed) and marked it as active. Ideally, this shouldn't have created a problem but it has.

Now when I start my computer I am shown an error which says :

Windows failed to start. A recent hardware or software change might be the cause. To fix the problem: 

    1. Insert your Windows installation disc and restart your computer.
    2. Choose your language settings and then click "Next".
    3. Check "Repair your computer"
.....

Unfortunately, I don't have a disk , so can't go down this path.

Also, I strongly feel that I need to make my recovery drive 'active' inroder to start my computer. Can someone help?

Thanks!