I've downloaded it a few times from seperate sources but I still can't get it to work. It tells me that it cannot detect a "valid Steam install". I know that I have a valid account. Can someone please help?

Many thanks in advance
A.Gentleman

take a look through this guide for help with installing.
http://www.unknownworlds.com/forums/index....showtopic=89619

the most important thing you need is Half-Life 1 installed (not HL:Source).