There is a theory, which seems to be bourne out by practise, which suggests that each version of Windows nicely uses up the resources available on a typical machine at the time it comes out. If you are just looking for an excuse to treat yourself and buy something new then go ahead. If your concerns are that your current machine is running a bit slow then there are various 'maintenance' tasks you can perform to make sure it is giving you all the performance it should. If you have been a bit lazy keeping the hard drive with Windows installed nice and clean, over the past few years, then the chances are that a good defragging and registry clean-up will make quite a difference. You will also find that the cost of things like memory for your old machine is now so much lower that an upgrade represents a trivial expense. You could also consider adding a second hard drive to it - properly deployed this could enhance performance too. Finally, do remember that there are many other choices of op systems apart from Windows and these are mostly more efficient and therefore run faster. It will cost you little more than a bit of your time to try some alternatives and see what you think.