vulpid :
I would prefer to do a fresh install as I've heard they're are malware problems with pirated versions of windows. Is this true?
To go about fresh installing would I do that from my windows, or would I wipe everything then go to the bios or something? Sorry if thats a stupid question.
There are heaps of Win10 install guides available. Here's one that looks okay to me at a quick glance:
http://www.expertreviews.co.uk/software/operating-systems/1401617/how-to-clean-install-windows-10-and-create-boot-media
RE pirated versions, yes, some come with all sorts. There's no way to know for sure. In any case, if you're prepared to do a fresh install it's a good idea, it's always the cleaner way to go.
Have you got an SSD already? If not, and if you have a bit of room in the budget, this would be the perfect opportunity to grab yourself an SSD. Just buy your Windows key and create the installation media (USB or DVD, instructions in the various guides including the one above). Then shutdown the computer, connect up your SSD and temporarily disconnect the HDD, boot up, install Windows on the SSD. Once it's all up and running happily, you can connect your HDD again (with power off), then boot up and clean it up or completely reformat it if there's nothing you want on it. You've then got your superfast SSD for the OS and key programs and the HDD to store non performance critical games/music/documents/videos, etc. Anything that won't fit on the SSD.
An SSD makes a massive difference to the responsiveness of the computer. It will boot and open programs waaay faster. Absolutely worth doing if you can afford it and don't have one already. We can make some suggestions if that's helpful?
The other advantage to that approach is that you install Win10 without touching your current build. So if something goes wrong with the install and you get stuck, you can always disconnect the SSD and reconnect the HDD again and boot back into your current copy of Windows to try and read up or figure out how to sort out whatever went wrong.
Not essential by any means, but for sure worthwhile if you can.