I do not have an option to boot from USB

SOURCE: USN external harddisk

You shouldnt need drivers unless its a Windows 98 PC. Right click my computer and select manage, when the box pops up select disk management. You should be able to see the drive and format it for use.

SOURCE: Lite on DVD Combo disk read failure

You could take the drive out of the encloser and hook it up. There could be a flaw in the enclouser ive had that happen before to me. I just took it out and put it in standard if this dosent work then there is a flaw in the dvd burner

SOURCE: I have Installed Windows7 on

- Windows 7 BSODs are often due toheating issues inside your computer. If you are using a desktop computer thentry to install a better cooling fan. Or simply you may turn off your computerfor sometime and start computer again. - BSOD may also happen when there islow RAM installed on the system. Some programs need more memory space to runand adding RAM would give your computer much needed boost. - One of the most important aspectof operating system is its registry. If there is minor corruption in this partthen it may lead you to errors similar to Windows 7 Blue Screen. There are somereadily available registry cleaners on the market. You may choose reginout asits secured. As we cannot stress enough thatmanual modification of registry is dangerous as well as difficult but anymistake in its modification can cause some of your programs to stop running. It would be wise to select aregistry cleaner that also offers you a feature of PC optimization. Using its PC optimizer feature youcan even remove browser junk, system junk and also manage the start up items toincrease the boot speed of Windows 7 computer.