Hi summer121, I understand that your sync account is not adding the bookmarks back to the new install of Firefox on this computer. I am sorry for the frustration.

Did you sign into sync with the new profile? and has the first sync completed? You can see a timestamp of the last sync if you go to about:config and search for sync.

If they are not there unfortunately sync does not provide back up services. Please always keep a copy of your profile before reinstalling.

These can't get your data back, but will help in the future.

These add-ons can be a great help by backing up and restoring Firefox

FEBE (Firefox Environment Backup Extension) {web link} FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backup of files that you choose.

OPIE {web link} Import/Export extension preferences