CDRom doesn't work and dll missings.

Hey

I am sorry I am writing in english, I just installed new XP op..

I was trying to install a new printer and I got some 'usb' sys files missings as: usbscan, usbprint

I downloaded these files and when the installation was about ending it says that I am missing 'dbghelp.dll' file

That error was appeared also when I tried to install WMP.

http://up203.siz.co.il/up3/wenzajzkznzy.jpg

Now about my CD ROM, it recognize only XP disks, other cd's wont appear on MY computer.

Also, When I am trying to boot from the XP disk when the pc is starting it is not working.

I don't know if this is the correct forum, so please let me know.

And I would be very happy to get some help

thankis.