Seeking Cost of Ownership/Maintenance Information

I’m seeking documentation on the cost of owning and maintaining Windows PC’s for all versions of Windows – 95 to present.

I have some clients who are still running Windows 98 PC’s and I’m getting tired of supporting those PC’s due to their frequent crashes. I want to be able to present documentation to my client detailling the cost of maintaining those older PC’s vs maintaining new PC’s.

Documentation can come from any source including Microsoft, but I don’t know where to look for this kind of information. Any help would be appreciated.

Thanks,

Brian.