You wrote, "i had viruses today so i used avast...." and also wrote, "i keep getting this virus thing from norton bout Backdoor.tidserv". According to the article Kees directed you to, Norton should be able to remove it, if you haven't removed Norton from your system. The instructions say to make sure your definitons are up to date and current. They also say to disable System Restore, and then run a full system scan in Safe Mode.
You wrote, "but i have'nt tried in safe mode". You need to follow all the directions, without skipping any steps. If you have a problem executing any of the steps, or don't understand something, please post back and don't hesitate to ask.
If Norton is the anti-virus you wish to keep, it's best you uninstall AVAST. Here is an AVAST uninstall utility, with instructions on how to remove it. If you wish to keep Avast, and uninstall Norton, here's a link to the Norton Removal Tool. It's best not to have two running at the same time. In this case, more is not better and can cause you problems.
Personally, I would uninstall Avast, for the time being and try removing Backdoor.Tidserv with Norton, as per the instructions. If you have followed all the instructions and find you still can't remove it, please post back. And when you do, kindly give us some information about your operating system, and any other details you can think of. It will help us, help you.
PS: If you find you still have a problem, after following all the instructions in the article, it wouldn't hurt to scan with Malwarebyte's again. But this time, scan using MBAM in Safe Mode, as you did with Norton.