Hi Elle,
Oh no
unfortunately, unless you were able to save your personalized lessons into an external/flash drive (or burned in backup CDs) I'm afraid it may be impossible to get your files back. But for the files you've previously uploaded you may simply download them from the Downloads Library or from your Account Management page -- go to My Files > My Uploads and you can get your own files from there, and for other users' files (the ones you downloaded before), just go to My Files > Little Reader.
Yes, you need to clear up your LR and LM activation records for your old laptop from your account. I think you already know how to do this, but just in case here's the Support article link:
http://support.brillkids.com/index.php/article/manage-activation-recordsAfter you've cleared up your old activation records, you may proceed to installing LR and LM in your new laptop, following the same steps you did when you installed LR and LM last time:
Installing and Setting Up Your Little Reader
http://support.brillkids.com/index.php/article/little-reader-install-and-setup-from-accountInstalling and Setting Up Your Little Math
http://support.brillkids.com/index.php/article/little-math-install-and-setup-from-accountI hope this helps! Do let me know if you need further assistance.