easyC 1.x is not Vista/Windows 7 Compatible and will not be supported.
easyC V2 2.9.3.2 and easyC Pro 3.1.3.2 are Windows 7/8 compatible.
easyC v4 all versions are Windows 7/8 compatible.
Note early versions of the Prolific USB to Serial cable are not Windows 8 compatible.
Please check out : http://www.intelitekdownloads.com/
and download the latest version of easyC