boot your pc with xp cd
go to recovery console by pressing R
run this command for drive c
assuming OS is installed in c: drive)
chkdsk c: /r /p
you can repeat this process
and better if you run this command for all other drives.
Since pc spec is low install only softwares you really need. Uninstall all unnecessary softwares. And as soon as you reinstall OS install an antivirus first and other softwares, drivers then. (don't install more than one antivirus and more than one firewall and install security apps which are light on resource)
You can use taskmanager to see which process is taking up much CPU Usage and Memory, identify the software and uninstall that software, or reinstall to recover corruption, or install the latest version of the software.
Defrag your drives and clean your registry(eg using CCleaner)
Go to RUN, type sysdm.cpl and enter
go to advanced tab
click on settings
Under Visual Effects tab select 'Adjust for best performance'
scroll down and put check for last 3 items(or only second last item if you prefer performance against looks)
click apply and ok
gud luck!
