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How do I reinstall Windows without a CD drive?


I have ASUS UL20A laptop, Windows 7, with Intel Pentium and a 320 GB with no CD drive. Now, I’ve lost the recovery CD which I can’t use anyway becausse I have no CD drive. But I want to format and completely restore my laptop to factory settings. But I’m scared that I will lose Windows 7. I cannot update my Windows on the Windows Update options. I’ve tried troubleshooting and manually downloading updates. But nothing works. It just gives me an error.

I’ll walk through the problems and options available for reformatting and reinstalling a computer with no CD or installation media.

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Time to Reinstall

So offhand I’d say, yes, that’s the right thing to do: reformat and reinstall. There are two problems here: one, the CD drive that you don’t have: two, no recovery media.

My recommendation for most people who have a computer that has no optical drive (some laptops and many netbooks) is to go out and get an external USB CD/DVD drive. It’s up to you if you want it to be just a reader or read/writer. But the important thing is that this drive will let you use recovery media, fresh installation media, whatever it is you happen to have.

The BIOS on your machine, I’m sure, will let you boot from a USB, an external USB drive. If that happens to be a CD drive, then you’re as good as having had one internally. So that’s the solution to the CD drive problem.

Lost installation disk

Losing your recovery media on the other hand is a tougher one to crack.

My recommendation there would be to start by contacting the manufacturer and see if they have a solution for you. Depending on the manufacturer (and unfortunately, I have no experience with ASUS so I can’t tell you if they’re one of the good guys here), they can often provide you with replacement recovery media once you’ve proven to them that you’ve got one of their machines.

The issue there is that, as I’ve discussed in other articles on the site, recovery media may or may not be enough depending on how the machine was configured.

Recovery or reinstallation media

Many machines will have a backup copy of Windows, if you will, on the hard disk and the recovery media will then simply access that. That’s why you would need the recovery media. Others will not and, instead of recovery media, what they provide with the machine is actually reinstallation media. Which includes a complete copy of Windows.

That’s actually my preferred approach, but it’s not always available. So start by going to the computer manufacturer and seeing what kind of replacement options they have for recovery and reinstallation media after you’ve gotten an external CD drive.

If they do not, or they’re unwilling to provide you with the media, the only solution that I’m aware of is to go out and purchase yourself a new retail copy of Windows 7. It will be more expensive, but if you want Windows 7, that’s really the only approach that I’m aware of to get back to a working state.

If you’re willing to, you can certainly investigate the free alternatives like Ubuntu Linux, but I’m assuming that Windows 7 is required for a reason and that’s the only answer that I really have for you.

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7 comments on “How do I reinstall Windows without a CD drive?”

  1. one OEM that I did tech support for at their call center got around this. What they did, is have the user boot a second computer with a cd drive from the disk. The disk then installed a recovery program onto a flash drive, that was then used on the computer without the cd drive. The flash drive was reusable, as long as it was not erased. That might be an option as well

  2. Just be sure to buy an external ‘DVD’ drive, not a ‘CD’ drive as most Microsoft media (ie: Windows and Office) are now on DVD’s.

  3. The standard Windows 7 installation media do an excellent job of providing all the essential drivers for most systems. (This even includes “fake” RAID, allowing you to install straight onto mirrored discs.) (Windows XP is often quite painful to install from its standard media. I’ve had to plug in a Wi-Fi dongle, which it did recognise and use, in order to let it go on-line and find the required driver for the on-board Ethernet. Windows Vista is somewhere in between, as you may expect.)

    The “bonus” applications, included by the PC/laptop’s manufacturer will need to be obtained separately, of course. In many cases, you may be better off without them. Some manufactures, e.g. Lenovo, make their applications available for download on their web sites. Often, there will be newer versions than those that arrived on your hardware.

    So, if you can borrow a standard installation DVD, or download and “burn” the ISO file for one, you should be back in business fairly quickly.

    I have used a retail edition Windows Vista DVD with a PC’s OEM license code, and I’ve read on-line that the same thing works for Windows 7. (For Windows XP, I had to change I386SETUPP.INI, as discussed in and elsewhere.)

    Ideally, obtain the correct DVD / ISO file to match the grade (Home Premium, Professional, Ultimate, etc.) of your license key. However, what is truly essential is making the correct choice between 32 bit and 64 bit versions.

    If you have a grade mismatch, you will need to modify sourcesei.cfg in the installation files (and either “burn” them to a new BOOTABLE DVD or arrange to run the installation from alternative storage). See, or try a tool that will create a modified ISO file that’s ready to “burn”, e.g. (To obtain an ISO file version of your (physical) DVD, you could do worse than read

    Please note that nothing I mentioned enables piracy, nor do I condone such practices. Rather, I have set out techniques that, I hope, will enable you to use software you are entitled to run, by virtue of the licence you purchased.

  4. Installing Windows 7 without a DVD reader:

    You can use a USB drive – flash or hard disc, of sufficient size (4 GiB or more), but – WARNING – any data you are already storing on it will be overwritten.

    A fairly simple technique is to use the wizard for Microsoft Standalone System Sweeper ( to install the bootable System Sweeper on your USB drive.

    Then, replace the “sources”, folder, on the drive, with the “sources” folder from the installation DVD. (You have either read the DVD on a computer that does have a reader, or you have got hold of the equivalent ISO file and are using techniques such as those discussed here, (The USB drive should have been given a file, “sourcesboot.wim”, and this is being replaced by “sourcesboot.wim” from the DVD. If the name on the USB was not “boot.wim”, but “.wim”, rename the file, copied from the DVD, to match.)

    Also, copy across all folders (and their contents) that are on the DVD but not the USB drive. (On my disc, these are “support” and “upgrade”.) Importantly, do not disturb the “boot” and “efi” folders or the “bootmgr” and “bootmgr.efi” files written by the wizard.

    One final change, you may possibly want to make, is to edit, or remove (allowing run-time choice), “sourcesei.cfg”, to enable selection of the correct grade of Windows 7 to match your license key. (See

    That’s it. You should now be able to boot from the USB drive, as described in the System Sweeper instructions, and run your installation.

    I think something very similar will work, if it’s Windows Vista you want to install.

  5. If your Asus computer came with a secret partition that will restore your computer to what it was when you bought it, then if your system has a provision to create a bootable DVD that will recover using that partition, you can use an external read/write DVD drive to create the above DVD and then boot from that.

    Better would be to see if there isn’t an F-key that you can press before Windows starts that will offer to restore the C: drive to the state it was in when you bought the computer. Try using google to find if other people have used this approach. They will no doubt mention what the key is, assuming there is such a key.

  6. On an ASUS machine press F9 when booting and Windows will be reinstalled from a secret partition. Their customer service unfortunately in my experience can be tricky.


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