How can I restore bookmarks after a computer crash?

If you have not used 'MozBackup' prior to the crash, the only way is retrieving your Firefox profile folder. With most Windows versions, the Firefox profile folder is stored under C:\Users\YourName\AppData\Local\Mozilla\Firefox.The folder 'AppData' and all its subfolders are usually hidden, so you'll have to make hidden files visible. After having reinstalled Firefox on your new HDD, copy the contents of the profile folder to your new Firefox installation. If you can't save the profile folder, your bookmarks are irretrievably lost.