If you install linux on a hard disk partition after windows,it changes MBR(Master boot record), and then if you remove the linux ,it will result in a non bootable windows.
To fix this just follow this steps and enjoy a clean windows booting.
insert windows installation DVD and boot from it,select repair windows option and then command prompt.
now run the following commands
>diskpart
>select volume 0
>list volume
this will list the drive letter of your windows DVD.(for example G)
>exit
>G: (or any other drive letter what you got)
>cd boot
>dir
>bootsect /nt60 SYS /mbr
now exit the command prompt and restart your computer,Enjoy.