delte everything except chrome (well save what you need)
start-->set programme defaults etc -->change or remove programmes-->off you go :D
if you really want to delete everything, you may want to run a "system revert", ie, reset to factory settings, i really cba to tell you here, go to http://www.online-tech-tips.com/computer-tips/restore-to-factory-settings-windows-xp-vista/
bish bash bosh, you have a make shift chromebook!
if you want to be geeky, just keep googling to customise how you want it