A quick solution to your PC would be to buy a USB memory stick for about £30 and keep it permenantly stuck into one of the USB slots. It will appear as a drive so you can then move your swap file on to it and also use it as an extra backup. By sticking a 8GB or so swap file on the stick you could find that the speed of access to it could be faster than the hard drive. USB comes in basic USB2 and USB3. If you PC is really old then it will have USB only, about 5 years ago it went to USB2 and modern ones are USB3. USB2 and USB3 are very fast indeed. All the USB types are backwards compatible so if you buy a USB3 stick you can put it into a USB or USB2 slot on the PC.

Having another flash based drive as a backup is also a good idea in case your hard drive fails regardless of whether it speeds up your PC.