Andy B, the XP operating system is a good one and loved by many, but be warned that Microsoft support for the system is ending in April so there will be no more security updates. If you intend to stay safe online you will need to change your system.
Some users of XP who are reluctant to give it up are installing Ubuntu and operating a dual boot system to retain the use of XP for a while longer.
With the amount of Malware around it is worth looking around for a replacement, in my view, as XP will become very vulnerable.
One particular threat to ALL systems is Cryptolocker Ransomware. Also consider installing a programme to keep it out!,
As it could be used to encrypt all your files it is worth regularly backing them up as it can be removed, but will take all your files with it unless you pay the ransom money demanded for the key!
http://www.bbc.co.uk/news/technology-25506020