Now buy a laptop without a OS at a very cheap price, go to https://ubuntu.com, download the iso file burn it on CD and boot from CD, YOu could install it even if you have windows installed, just download a iso file called gparted burn it on cd and boot it, the funda for installing linux is very easy, while using the partitining manager, gparted whcih can be downlo leave your c drive, install it on the d drive after NTFS partition use 500 mb for swap partition and the rest 3 to 4 gb( you could even use 1 gb but the space will go to waste.
the rest partition as ext3 or ext4, then boot the ubuntu cd ubuntu desktop will appear with a icon install, click on that it will ask you normal question like language location date time, then it will come to partition it will show you your windows partition and the rest as ext 3 and swap just click on the swap partion after ntfs drive click on "swap" apply, then click on ext 3 /ext4 partition, clik on the "/" sign do not reformat as you have already done that using the gparted cd the system will install, remove the ubuntu cd and restart you will see a menu with ubuntu first then last would be windows, press enter and ubuntu starts.
Why Ubuntu? Fast free virus free os