My brother merged two drives of pc i.e C and D drive into One i.e C drive.
now i am not able to uninstall the softwares that where in D particularly the AutoCad NOR am i able to Install it from the start.
You can try Revo Uninstaller, or GeekInstaller, but I don't hold out much hope. You can also try by hand to remove entries from the hard drive, and from the registry, but it's bound to be pretty complicated.
If the software solutions I suggest fail, you may be looking at re-installing the OS.