Doesn't really matters abt ur english
U wrote well
BTW u can use System File Checker to avoid re installation of windows but remember that your other programs might not run
Try this to repair windows
Go To run
Type SFC /SCANNOW
A window will pop up & will repair any of altered windows file
Alternatively you can pop your Windows CD into ROM at bootime (set the CD rom as 1st boot device) then repair the windows from there
Put avast as antivirus if you can & update it frequently