Hi, I clicked on 'Replace all data on this computer with my Sync data' option in 'manage account > sync reset'. and canceled the process before it end. but everything has already deleted.
So I went to 'Sync' tab in the options but I found it like this http://i.imgur.com/cCtCO.png
I deleted Firefox using Revo Uninstaller to completely delete it, And reinstalled it but nothing change the sync tab wont appear normally! I even go back to a restore point but it's the same!!
Note: When I click on 'Firefox > set up sync..." and choose 'I have an account' it appears like this http://i.imgur.com/IVpI9.png
What that's mean? I want to sync THIS computer not another one!
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).
Do not click the Reset button on the Safe mode start window or otherwise make changes.
Thanks for your reply.
I did as you told me but it's the same
And I have no extensions nor themes right now because the sync deleted it. so it's impossible to the add-ons to have any thing to do with this.