Yes. You don't need to have a DVD drive for installing Win7 necessarily. If you have the whole Win7 setup files in a flash memory or other portable devices or if you just have it as an image file (e.g. *.ISO file) you can simply install it. Of course it could be illegal but technically possible!
Yes, if the computer is connected to a network there are options for installing Windows that way.
Yes, but you must copy ALL of the files from the disc to a USB thumbdrive and install it through a USB drive. If you don't have a USB drive, then you cannot install it.
It is possible, using a USB drive, however I am unsure fo how it would be done. I am sure that there are instructions online...
Any windows OS you want.
Yes. Many Linux distributions can be easily booted from a USB Flash drive. With some modification, booting Windows XP is also possible.
Yes.
You can install Windows or Linux using a USB memory stick.
It is possible to install Windows 8 using a USB flash drive with at least 4 GB of space. The process requires creating a Windows 8 ISO, or buying Windows 8 as an ISO, and adjusting the computer's BIOS to boot up from the USB drive rather than the hard drive.
You can install it from a flash drive or through network.
Nope - to recover your Windows 7 system - you need to use the recovery partition on the hard-drive.
Yes, you can order the multiple set of Vista CD's from Microsoft after you purchased the Vista DVD, Windows vista comes on a single DVD and one recommended hardware requirements for Vista it's a DVD Drive.
Did you install Windows XP to the hard drive? New hard drives do not come with an operating system; to boot from it, you have to install one on it.