Help, I have lost my accounts on T/B but not yet the data

HELLO ALL,

I am facing a serious problem, that will cost me 4 years of hard work to be lost..
I established four accounts in one version of T/B, and were working properly, until 2 days ago, the software was not able to log to show me any message.. it is clear that the data is there since the size is more than 12GB still exist.. but now it is starting as if T/B has been installed from start.. and asking for accounts configuration..
Please, help me cos am not willing to be starting from scratch..

Thanks in advance