as mandolin said, you need to open up your account in the cakewalk store.
I still have all my products in there as well (with serials/codes) including sonar 7XL home studio.
theres nothing we can do when it comes to serials. that's company business.
youll have to either wait for email support to get back to you or look through your old emails and try to find the info.
for what its worth, I would keep home studio retired along with the laptop :-)
you can download a free trial of sonar. I think you would be pleasantly surprised
how far technology has come in the past few years.
this will give you a great trial of a new product and let you try out some fancy stuff.
there came a point years ago where 7 XL was good but it couldn't keep up with my demands.
another thing to consider is this new PC you have, it might not even support sonar XL anymore.
I believe it ran on XP and Windows 7. not sure about 8, but probably not win 10.