Hello, I am a computer teacher so I have to deal with various types of sofwares hence need a fast and updated operating system I am using windows 7 professional since 6years before this time period I am using windows Xp which is also much faster on low ram pc's but now I have to deal with various new generation softwares like corel, cc, lightroom which needs updated operating system and does not work on Xp windows so I before 6 years I switch to windows 7 pro which is as fast as xp and also supports all type of new software.
Nowadays, windows8, 10 was also prevailing but they are too slow on low ram pcs and can leisure your pc, laptop.
If u have a pc with 2gb ram most suitable and updated window that fulfill all your needs is windows7.and if u are a i3, i5, i7 user you can also try windows10, 8 as they are updated and more proficient than windowsXp.