YOU WILL GET A BETTER RESPONSE IF YOU DESCRIBE YOU PROBLEM IN THE TOPIC TITLE
If the system had worked previously OK then there was no need to mess around inside the PC.
If your registry cannot be repaired then its time for a clean install of the OS
As for setting up your drives they should be put back to the same as before you tampered with the inturnals, but if you are unable to do this then try HERE
for a simple guide to installing a DVD burner which is similar to installing CD drives
This is my first and last answer to your problem
There is no need to post the same query and start 4 new threads on the same subject.