There is already a big hole in Internet Explorer 6 - 11 which is patched on > Xp So that's the first one.
WIth that one you have to visit a per say web site and then there is a possibility that they can take control of your profile.
Use it as a tool to surf the internet with. But remove any sensitive information on there. There was talke of a chinese company continuing with the XP security fixes as 50% of china is on xp so dont feel your the only one on XP.
Go into many establishments and there still on XP.
For total peace of mind its about £80 - £100 for a Win 7 Disc.
Worries are now gone