Press F1 key to initiate the recovery process.

Press the right arrow within setup to go to the Boot menu.

Press the down arrow key to select “Boot Device Priority” and press “Enter”.

Change the first boot device to CD-ROM by pressing the down arrow until “CD-ROM” is displayed.

Open CD – ROM tray,insery system recovery disk,exit from BIOS set up by pressing “F10″,select “save changes and exit” option

If you do not have a restore CD, you can contact Compaq to order one.Allow the computer to boot up from the restore CD.

Restart computer,it will begin recovery process automatically.You have to select the Operating system with which you pc was shipped.You have to put in operating system CD when prompted.The it will ask for license key you have to fill it.

Just follow other instructions and thats it.

USB Pen Drive (Min 4 GB)

Windows 7 ISO (32 bit or 64 bit)

MBRwiz Download and Extract it on your hard drive (Diskpart utility for Windows XP doesn’t detect USB drive as Disk hence we need to use this free utility to make bootable USB drive).

1. Put you USB Drive into your computer and connect your USB Flash Drive to your computer for formatting the USB drive,

2. Double-check that your drive is big enough to accomodate the Windows 7 install source of 2.2GB.To Format USB Flash Drive Go to My Computer -> Right click on USB drive and select Format from context menu.

Format USB Drive

or you can go like this after formatting the pendrive

Insert your Windows 7 Install Media into your DVD drive (or mount the ISO) and copy the contents of the DVD over to your USB drive.

Make USB Drive Bootable

When the Command Prompt opens, enter the following command:

DISKPART and hit enter.

LIST DISK and hit enter.

Once you enter the LIST DISK command, it will show the disk number of your USB drive. In the below image my USB drive disk no is Disk 1.

In this step you need to enter all the below commands one by one and hit enter. As these commands are self explanatory, you can easily guess what these commands do.

SELECT DISK 1 (Replace DISK 1 with your disk number)

CLEAN

CREATE PARTITION PRIMARY

SELECT PARTITION 1

ACTIVE

FORMAT FS=NTFS

(Format process may take few seconds)
ASSIGN

EXIT

Don’t close the command prompt as we need to execute one more command at the next step. Just minimize it.

5. Insert your Windows DVD in the optical drive and note down the drive letter of the optical drive and USB media. Here I use “D” as my optical (DVD) drive letter and “H” as my USB drive letter.

6. Go back to command prompt and execute the following commands:

D:CD BOOT and hit enter. Where “D” is your DVD drive letter.

CD BOOT and hit enter to see the below message.
BOOTSECT.EXE/NT60 H:

(Where “H” is your USB drive letter)

7. Copy Windows DVD contents to USB.

You are done with your bootable USB. You can now use this bootable USB as bootable DVD on any computer that comes with USB boot feature (most of the current motherboards support this feature).

Note that this bootable USB guide will not work if you are trying to make a bootable USB on XP computer.

Following is the more illustrated way to make usb drive bootable

http://www.bootdisk.com/pendrive.htm

To write the master boot record on a USB drive that is compatible with Windows 7, we use the Microsoft bootsect. This allows us to write the correct code for the boot drive letter. Open a command prompt and go to the boot CD. From there, enter the following command (where you change the last argument, E: drive letter for your USB drive), Microsoft bootsect enter the appropriate letter from the Master Boot Record should target OS operating system loader. / NT60 option is to write the master boot code, which works with Windows Vista and Windows 7 systems using Bootmgr. If we do not install XP, we use / NT52 switch that says NTLDR compatible boot record.

BOOTSECT.EXE /NT60 E:

Pull out USB drive and take it across your computer requiring Windows 7. Now reboot your computer and press F9 to get your BIOS screen and select USB drive as your boot drive.If every thing goes fine, Your Windows 7 Installation should start from your USB drive.