If you have a USB-flash drive laying round you can also use that to install windows 7
Guide:
#) Mount the windows 7 iso image with daemon tools
#) Run diskmgmt.msc and see which disk number is your USB Flash Drive (say it's disk 1)
#) Run cmd and type :
1) diskpart
2) select disk 1
3) clean
4) create partition primary
5) select partition 1
6) active
7) format fs=fat32
8) assign
9) exit
#) Type xcopy d:\*.* /s/e/f g:\
supposing d: is the virtual drive letter and g: is the USB Flash Drive letter
Now restart and boot from the USB Flash Drive