I also have Samsung N150 netbook
The way Installed Windows 7 from pendrive was use " unetbootin-eeeubuntu-windows-276 " free application to load the .iso image on pendrive and just manually install it like you would do from a DVD
Dont try to boot it, install it from pendrive disk drive manually and thn whn new windows is installed, just delete your windows.old directory as it have ur old windows file
Steps are same for XP