Windows 7: Will Activation key for Original Win7 Work with a Newer SP1 CD?

I have a legit Windows 7 Home Premium (x64) OEM disk and key (without SP1), and updated to SP1 online some time ago.

I now wish to re-gen the system to produce a cleaner operating experience (get rid of a lot of the unnecessary junk that I have accumulated). My neighbour has a legit Windows 7 Home premium x64 disk, newer since it includes SP1.

Can I use his disk to install on my PC, use my legit key, and get the benefit of already having SP1 without having to go through the experience of the two-step process (original, then update to SP1) with my CD? Not a big deal, but a valuable option for the bandwidth-challenged consumer.

Well of course. Its still Windows 7.

Strange. Because someone created a slipstreamed SP1'er for me, and it wouldn't accept the product key from my original CD/DVD.

My OEM Home Premium key worked with install media that included SP1. My original disk didn't have sp1. My current sp1 DVD was burned from an ISO created from an original Microsoft DVD, not a slipstreamed disk. If you can find a good reliable official Microsoft ISO it should work. The site I got mine from is no longer hosting the files so I can't help you there.

Digital River offers downloads of original MS Windows 7 ISOs for free.

For details, check out the link below:

Windows 7 Digital River direct links: Multiple Languages; X86 & X64 - Page 60