Are you sure you're flashing 5.0 for the N900T? I don't see one listed on SamMobile. There are 5.0 files for other models, but not the T. The BEST result you can get from flashing a ROM for another model is a failure. In some cases it causes damage to the motherboard, and you have to have it replaced. You're lucky it failed. Wait until there's at least 5.0.2 for the T. (That's the bug fix for 5.0.1, which was the bug fix for 5.0, which was as buggy as a flea circus. Even 5.0.2 still has some bugs, but maybe you can live with them. Or wait for 5.1 and read some of the reports.)
And back up everything before you even do an update (assuming you don't always have everything backed up, which you should - truck tires don't leave much data when they roll over a dropped phone).
(In your other post you said N900. Which is it? The N900 isn't the N900T - they're different phones. A ROM for one won't work on the other.)