Buyer Beware Flash Drive What Things Should I Look For When Looking At Second Hand Lap Tops As Far As Being "buyer Beware"?

What things should I look for when looking at second hand lap tops as far as being "buyer beware"? - buyer beware flash drive

Not sure about these books at such a seemingly extended up to 20 local vendors (if it happens every month to 6 weeks or less)

I remember the last time I did a search with one of his newspaper classifieds last Saturday before the start of this year's time, said the tower drinks came with MS Windows XP (system) in operation, but "it does not match the actual CD come-ROM that is installed with it, should for any reason - you may need to reinstall. I have never used a PC / Windows-compatible computer at home before, not for personal use outside of schools, libraries, Internet cafes and UNI, so I have no experience or prior to the installation of Microsoft-issued software.
And if it is necessary to install an operating system on your PC, not at regular intervals or every year, right? Is this a myth - that all too often it is necessary to completely reinstall the operating system.
I am also concerned about whether the spirit of Microsoft's operating system and desktop software for use 2nd Hand?