yesterday i accidently uninstalled something called realtek audio device & now have no sound on my computer. what is the solution to repair my user error ?

Welcome to D-A-L.

Download, install, and run Everest Home Edition (CLEAN FreeWare) on this machine. Once it's finished loading and running, look under;

MOTHERBOARD
Post what is listed for your Motherboard (make/model) and the Motherboard Chipset description.

Multimedia, or, under Multimedia, PCI / PnP Audio. This will tell you what sound devices you have available on your system.

Post that information exactly as presented by the program.