"duplicate on the network" means your computer name is the same as another on your network. Change your computer name.

You can do this by right clicking on My Computer and selecting Properties.
Click on the Computer Name tab then the Change button.
Make the name something unique.
Note: Don't confuse Computer description with Computer name, they are not related.

As for the unknown devices in Device Manager:

Right click on each in turn and select Properties.
Click on the Details tab.

There will be a line like this:

PCI\VEN_nnnn&DEV_nnnn&..........

Post that much from each. You can then (or we can) search Google and that will almost always tell you what kind of device it is.

I did it!
They're all done.
I just want to know how to get rid of that error message.
It says
System Error.
There is a duplicate name on the network.
(something close to that.
And once that riddle is solved,I'll be done(thank god!)

OK..sorry,I don't see that last post you made.
Everything is working good now.
You really rock!
You were so patient with me all this time.
Thank you so much!
I hope next time I need help,I'll get you again.

By the way..the 2 unknowns were an infared driver and something else.
I just went one by one downloading each driver and they were the last 2 on page 3.LOL
Thanx again.
Please buddy me or whatever so I can ask you advice if I need to.