I recently bought an ASUS N53SV, due to problems that resulted in frequent blue screen and crashes(Mozilla, Chrome etc). I decided to download and re-install a fresh copy of Windows 7 Professional 64 bits from digitalriver. Beforehand i ran diskchck, everythings seemed fine. I tried methods like booting from a USB stick, safe mode and just a double-click on Setup.exe but nothings works. Installation gets stuck halfway and i get the message : "Windows cannot install required files The file may be corrupt or missing.. Make sure all files required for installation are available and restart installation. error 0x80070570" The same iso file worked on other laptops. Also tried by downloading from other sources. I got fed up did something stupid . While booting from USB, i formatted the C: drive which is the only primary partition with an operating system. The installation failed once more and now when i start up the machine i get : "BOOTMGR is missing press CTRL+ALT+DEL to reset" I have unlimited amount of Windows 7 Professional keys from my uni and another laptop available. Please tell me what to do. Asus did not come with an installation dvd. If necessary i could buy a new retail windows 7 but will that work since nothing is left on the hard disk to start the installation? Can i still enter BIOS? Please help i will constantly recheck this post if you need more info.