Most larger computers and laptops come with a system recovery CD that you can use in the event that you need to repair your device. However, netbooks often don't have a CD/DVD drive and, therefore, can't be fixed with this type of disk. To make up for this deficit, you can use this trick to make a system repair USB key, which can be used on both netbooks without CD/DVD drives and PCs.
Create a System Repair USB Key on Windows 7
In order to complete this process, you will need a bootable USB key with over 165 MB of free space.
Preparing the USB Key
Open the command prompt, and go to Run. Type CMD, and press Enter.
Next, enter DISKPART, and go to list disk to open the DISKPART tool.
Look for the number assigned to your USB key from the list that appears, then enter select disk [number of USB key]. Click Clean.This will delete this partition.
To create a new one, enter create partition primary, and go to Active.This will make your partition active (bootable). Continue the process by entering format fs=fat32 quick then assign.
To exit both DISKPART and the command prompt, type Exit twice in the field.
Display Hidden Files and Folders
Go to Start > Computer > Organize > Folder Options and Search > View tab.
Check the box next to View hidden files, folders and drives. Uncheck the box next to Hide extensions for files whose type is known and Hide protected files of the operating system.
Creating Directories and Copying the Necessary Files
Create a folder on your desktop called Win7. Open the folder, and create two folders titled Sources and Boot:
Copy the C:WindowsBootPCATbootmgr file in the Win7 directory.
In the boot directory, copy the C:WindowsBootDVDPCATboot.sdi, C:WindowsBootDVDPCATBCD, and C:WindowsBootDVDPCATfr-FRbootfix.bin files.
In the source directory, copy the C:Recovery486aab42-cf02-11de-be22-c44fb1debe9dwinre.wim file:
Copy the contents of the Win7 folder to the USB key. Rename the BCD file to bcd and the winre.wim to boot.wim on your USB flash drive.
then it does do chkdsk