I have installed Windows 7 from USB, but when I plugged out USB and start windows after shutdown windows dont start. It says Insert Win Bootable CD to continue.
I installed win 7 from USB then upgraded the win7 to 64 bit dirctly from Hard Disk.
Kindly suggest the solution.
Create a "system repair disc" on a CD by typing that into the start button search box and run the wizard, then restart with the disk in and the USB device not connected to repair your bootloader.
If you don't have a CD/DVD drive, just create the repair disk on a USB stick like THIS.
If your computer will not boot at all no matter what you do, I would download the Windows 7 64 bit SP1 image from DIGITAL RIVER and create a bootable install USB stick with the 64 bit version and do a startup repair or REPAIR INSTALL.
If you do a repair install use your key to re-activate. Any problems with the activation online (unusual event) you can call MS at (888) 571-2048 and get it done quickly, usually without even talking to a person.