That's nonsense. First of all, there's basically no way that botching an OS install should be able to damage hardware, and for anything other than a hard drive

That's nonsense. First of all, there's basically no way that botching an OS install should be able to damage hardware, and for anything other than a hard drive problem the vast majority of retailers will accept returns with the drive removed (for privacy purposes). Even more importantly, though, the written Newegg policy allows customers to install a different OS without voiding the warranty; the problem is that Newegg is apparently doing a very bad job at educating their CSR's of what their policies actually are.