Just about any version will work for a clean install, even it it's branded. A generic OEM or retail version will be fine. Usually pressing F12 at boot time brings up the boot device menu, which will allow you to select a boot device. 
Hello folks, I have a Dell Inspiron One  20 with a German version of Windows 7, 64 bit.  I would prefer to change to an English version but am running into difficulties.  I have a 32 bit Windows  DVD but cannot boot from the disc. The PC ignores my instruction to boot from the disc. Please advise how to install my Windows 7.  If this is possible will I need to download Dell drivers I understand Windows 7 64 bit is preferable for the PC; do I require a Dell version, if I choose to go with the 64 bit Thanks in anticipation  John Mathis 
Install Windows 7