reformat windows using USB?

Yeah,you can.Why don't you repair it? Repair it can helps you improve you level about computer.Usually,disk c is person's system install files .You can find what changed in it,the files turn bigger or someone is unusual .

Yeah! It is feasible to boot your pc from a flash disk as long as your pc supports it. I have made my flash disk bootable with a specific tool. My flash disk contains many use applications and tools used for computer troubleshooting and maintenance, and also a PE environment which is very similar to windows xp's interface. Very handy to take with! I always use it to help my friends and colleagues to maintain their pc or reinstall operating systems from the flash disk.

you can boot from a USB drive if its made bootable with OS. Most desktops mobos are not configured to boot from a USB device. Even in the bios when you can pick the order of boot devices it will not have USB listed as one on the options. Most all laptops have the option to boot from USB or external device

u can do it usign the comand prompt btu u can also use the usb if u have enabled the USB in the BIOS happy lottin and have a nice day

You can reinstall the OS with your USB drive and you need to have the copy of os installations files which is different from the regular files in the Installation CD. Also to start the installation we need to change some configurations in DOS prompt, but for the beginners it is somewhat tough job and only those having experience can do.In case of failure of installation of US with USB, this may cause some problems in the regular installation with CD as we have made some changes in the OS. Consult some system admins, if you are not able to repair your ROM drive.

yes you need to have addition files on your thumb drives other than the installation file.. go here http://www.eeeguides.com Because most eepc does not comes with a dvd/cd driver there are article there to teach you to install Xp using a thumb drives.