I have formatted my hard disk in my thinkcentre and now none of my devices like speakers are working?

I think you are not downloading drivers for proper model else we also use Lenovo ThinkCenter and download drivers from its site. Go to Programs->Accessories->System Tools->System Information and take model no and download drivers for the same. Then and then it will work.

If you can have universal drivers disk it can also resolve your problem.

There's a free, and reliable, utility called Slim Drivers, that scans your system, identifies all the components and finds the latest drivers for them. It then invites you to install them, and if you agree it updates them. I've used it many times and find it extremely thorough, safe and reliable.

You update your windows.
it will automatically install all drivers.
this is best thing.