How to change Display Language on Windows

1. Open Regional and Language Options by clicking the Start button , clicking Control Panel, clicking Clock, Language, and Region, and then clicking Regional and Language Options.

2. Keyboards and Languages tab.
   

3. Display language, choose a language then click OK.
   

1. Open Regional and Language Options by clicking the Start button png">, clicking Control Panel, clicking Clock, Language, and Region, and then clicking Regional and Language Options.
   

2. Click the Keyboards and Languages tab.
   

3. Under Display language, choose a language from the list, and then click OK.
   

For XP
Steps to change the default system language (Windows XP)

1. Open the Control Panel.
2. Open Regional and Language Options.
3. Click the Languages tab.
4. Ensure Supplemental language support items are checked.
5. Click the Advanced tab.
6. Select the language from the list in the Language for non-Unicode programs.

Windows 7

1. Open Regional and Language Options by clicking the Start button, clicking Control Panel, clicking Clock, Language, and Region, and then clicking Regional and Language Options.

2. Click the Keyboards and Languages tab.

3. Under Display language, choose a language from the list, and then click OK.

Im assuming that the question is the operating system, commands, etc are all in spanish. You did not specify your operating system so unsure about what version or manufacturer. The instructions below will work for Vista... similar instructions can be done in XP and Win 7.

1. Open Regional and Language Options by clicking the Start button , clicking Control Panel, clicking Clock, Language, and Region, and then clicking Regional and Language Options.
   
2. Click the Keyboards and Languages tab.
   
3. Under Display language, choose a language from the list, and then click OK.
   
4. Open Regional and Language Options by clicking the Start button , clicking Control Panel, clicking Clock, Language, and Region, and then clicking Regional and Language Options.
   
5. Click the Keyboards and Languages tab.
   
6. Under Display language, choose a language from the list, and then click OK.
   
7. Open Regional and Language Options by clicking the Start button , clicking Control Panel, clicking Clock, Language, and Region, and then clicking Regional and Language Options.
   
8. Click the Keyboards and Languages tab.
   
9. Under Display language, choose a language from the list, and then click OK
   

f you have windows XP follow these instructions. If you have Windows Vista follow the second set of instructions. 
Windows XP

1. Click 'start'
   
2. click 'control panel'
   
3. click regional and language options'
   
4. Under the first tab called 'Regional Options' there is a drop down arrow,click it
   
5. setlect your prefered language
   
6. click ok
   

In Windows Vista 1. Open Regional and Language Options by clicking the Start button , clicking Control Panel, clickingClock, Language, and Region, and then clicking Regional and Language Options.
2. Click the Keyboards and Languages tab.
3. Under Display language, choose a language from the list, and then click OK.

Please don't forget to rate my answer. Good luck!