My initial perspective on your issue is: You had QB desktop, your computer failed, and you want to transport the old data to QB Online. 1) Depending on why you PC failed, you should be able to get the harddrive out and retrieve the QB company file(s), either on your own or with some assistance. 2) Yes, you should be able to have QB assist you with moving your files to the cloud.
Secure any file of *.QBW, *.QBB, *.QBM, and *.ADR from your old hard drive. Reinstall QB Desktop on the new machine to restore your file. If you are using QBD 2018 or an older version, utilize the trial version for QBD 2022 to upgrade your file and migrate it to QBO.