is this a virus?

[alych]

when i open a word document in my laptop it always duplicate itself with a different character but when i close the word document the duplicated file is also gone 

[BC_Programmer]

that's a small temp File word creates.

[alych]

how can i stop it from duplicating the file 

[BC_Programmer]

it's not duplicating the file, it's a temporary file that word creates:

more info:

http://support.microsoft.com/kb/211632

[evilfantasy]

Sounds like you have Hidden Files and Folders set to 'Show all'

[alych]

how can i stop it from creating temporary files

[evilfantasy]

• Right Click Start
  
• Select Explore
  
• Select Organize
  
• Select Folder and Search Options
  
• Select the View tab
  
• Under the Hidden files and folders heading uncheck Show hidden files and folders
  
• Select the Hide extensions for known file types option.
  
• Select the Hide protected operating system files (recommended) option.
  
• Click yes to confirm that you really want to do this.
• Click Apply
• Click OK

.
You may need to restart the computer for it to take effect.

Those files 'should' stop appearing now.