64 bit windows is desirable this days, if you don0t have a reason to use 32 bit windows, say to it good bye
now, be sure the guy used the right windows 7 license, not activated with the wrong license
if your pc has a windows 7 license sticker with 25 letters and numbers
run this program
http://www.nirsoft.net/utils/product_cd_key_viewer.html
it will show you what license he used, if he used a different one, i would advise you to change it to the one you do have, often when someone installs windows, they use the wrong version, so you would need to use this link
https://www.microsoft.com/en-us/software-download/windows7
to get the right installation disc and do a new install with the right license