We use the following Windows installation images:

Windows VersionImage Name

Windows Server 2008 R2

7601.17514.101119-1850_x64fre_server_eval_en-us-GRMSXEVAL_EN_DVD.iso

Windows Server 2012

9200.16384.WIN8_RTM.120725-1247_X64FRE_SERVER_EVAL_EN-US-HRM_SSS_X64FREE_EN-US_DV5.iso

You may download them using one of the following links: