Problems with the languages in my windows

Question

I have made an aplication that uses some windows. In these windows appears some buttons. My problem is that the words in the buttons appears in english in some computers and in spanish in others. How can I do for set the language in spanish?
For example, in some computers is written "Aceptar" and in others "OK".
Thanks.

Answer 1

I can't copy it exactly since I don't know this account's PW and I only have it saved on this comp (my imac) but I can type it.
Also, it's having a problem it had before in that it's not going to sleep when I go to apple menu -> sleep. It takes either a few tries or it takes a little bit to go to sleep.
BatteryInformation:
  Model Information:
  Serial Number:  W0020TU7LE1LA
  Manufacturer:  SMP
  Device name:  bq20z451
  Pack Lot Code:  0000
  PCB Lot Code:  0000
  Firmware Version:  0201
  Hardware Revision:  000a
  Cell Revision:  0165
  Charge Information:
  Charge remaining (mAh):            4741
  Fully charged:            Yes
  Charging:            No
  Full charge capacity (mAh):            4834
  Health Information:
  Cycle count:   229
  Condition:   Normal
  Battery Installed:       Yes
  Amperage (mA):       -1364
  Voltage (mV):       12203
SystemPower Settings:
  AC Power:
  System Sleep Timer (Minutes):       10
  Disk Sleep Timer (Minutes):       10
  Display Sleep Timer (Minutes):       5
  Wake On AC Change:       No
  Wake On Clamshell Open:       Yes
  Wake On LAN:       No
  Display Sleep Uses Dim:       Yes
  Battery Power:
  System Sleep Timer (Minutes):       10
  Disk Sleep Timer (Minutes):       10
  Display Sleep Timer (Minutes):       5
  Wake On AC Change:       No
  Wake On Clamshell Open:       Yes
  Current Power Source:       Yes
  Display Sleep Uses Dim:       Yes
  Reduce Brightness:       Yes
HardwareConfiguration:
  UPS Installed:       No
ACCharger Information:
  Connected:           No
  Charging:           No