After fresh installation of xp, Keep a registry backup. Its better if you keep a image of your c drive. By that you can reinstalled xp with in 5 minutes.
After fresh installation-
1> Open command prompt and run CHKDSK with the /F (fix) option to correct your Hard disk problem.
Just sure that there is no any hard disk problem like bad sectors.
2> Use a strong antivirus for protect your system.
3> Dont use unsigned/unknown software.
4> After installation of some software don't try to uninstalled it, this may cause some dll file or system file may uninstalled which may effect your system. you know some software are using same dll or defendant dll file from the system.
5> Use UPS , as after power failure and if system directly shutdown then system file may corrupt.
6> Avoid UN-proper shutdown.
7> Most important thing is that large file copy or moving from one drive to another, wait for completing.
8> Create a system restore check point.
9> Finally check your hard disk data cable, if u think it has some problem then changed it.
10> Don't pressure on processor with opening with a lot of application simultaneously. You can check it by pressing right click on Task bar and select task manager then goto process tab and check your cpu usage.