Thank you all for your valuable response. I want tell you as to why this question arised in my mind.
My friend uses pirated version of xp and to frankly saying it looks much better than win98.
But whenever he tries to connect to net after couple of minutes the machine restarts. Not only does it restarts but sometimes his taskbar is missing or some critical error occurs and everytime the machine restarts it does scandisk. But this problem does not arise when he uses win98 (which is also pirated). He has all those anti-virus, security and anti-spyware software installed in both OS. But these software dosen't show any kind of virus or other activity.
One more thing he use bsnl broadband internet service.
So if u people could help to solve the problem, it would help me to decide whether to upgrade, because if I go on and use genuine version,whether I would have this kind of problem or not.
As I already have a copy of pirated xp disk which he has given to me, but I don't want to use it.
My main question is that would this kind of problem would arise if I use genuine xp?