Yeah its hardly a trcik, but Microsoft wouldn't exactly document it either.
I once had to put Windows 95 release A onto a computer that was running Release B, I coudb't delive it, doiong a down grade on the o/s instead ofan upgrade, well that was my school for you, always backward at being forward!
That was what I did though, renamed Win.com and it worked! I did that too with Win 98 SE, wanted to upgrade Win 98 first edition, but wasn't as successful.
Hmm I wonder is some moron will try and upgrade Win 2K with Win ME ?? No wait a minute I expect someone already has , my old school!!
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My Computer
Pentium II 350
Gigabyte 6BXC M/B
16 meg Voodoo 3 2000 AGP
128 Meg of RAM
18 gig Western Digital Expert HDD UDMA 66
Sound Blaster Live ! 256
56k Modula Tech V90 USB modem
4 x SCSI writer
Advansys Host SCSI controller