help with dl145

[captain kirkhere]

Hi.
I have purchased a dl145.
I cannot get it to boot. The previous owner had the same problem.

When I reset the cmos it will load bios so I attempted to install an operating system but my key is bad. I don't think this will fix the problem with booting anyway because when I try to fire it up again, I have to clear the cmos again to get it to get ready to install an os.
Can you tell me how to proceed to get it to finish post reliably without clearing the cmos each time?
I will load a linux OS if you can tell me which one is best. I want to set up a home server and put all my movies and pictures and music on it. I don't want to throw good money after bad.
Thanks