Q: i can`t download os x 10.9

See http://support.apple.com/kb/HT5842

To install Mavericks you must have a MacBook 5,1 or later.  Same for Mountain Lion.

Ralph Landry1, how about for this one? Do I need more memory? And, how can one tell the date on the computer since I bought it from a friend? I appreciate your coment.

Model Name:          MacBook Pro

  Model Identifier:          MacBookPro1,1

  Processor Name:          Intel Core Duo

  Processor Speed:          1.83 GHz

  Number Of Processors:          1

  Total Number Of Cores:          2

  L2 Cache:          2 MB

  Memory:          2 GB

  Bus Speed:          667 MHz

  Boot ROM Version:          MBP11.0055.B08

  SMC Version (system):          1.2f10

  Serial Number (system):          W86141FYVJ2

  Hardware UUID:          00000000-0000-1000-8000-0016CB8D0E63

  Sudden Motion Sensor:

  State:          Enabled

That will not qualify for anything above Snow Leopard, Mac OS X 10.6.8.

To use Lion, 10.7.5, you must have an Intel Core 2 Duo, i3, i5, i7, or Xeon processor, 2 GB ram and 7 GB free HD space.

For Mountain Lion and Mavericks, you must have 2 GB ram and 7 GB free HD space and:

iMac 2,1

MacBook 5,1

MacBook Pro 3,1

MacBook Air 2,1

Mini 3,1

Mac Pro 3,1

XServer 3,1

Yours has an Intel Core Duo and is a MBP1,1 which will limit you to Snow Leopard.

You can find out more about the machine and possible upgrades by going to http://www.everymac.com and click on the type of machine (MacBook Pro) and then find the Core Duo 1.83 GHz and see that it matches the model identifier (1,1) and from the description you can get the time period during which that one was in production.