As I read it Stevie bought extra memory and then decided to transfer files onto an external hard drive as well? Whatever, the problem is the same whatever happened.
First thing is that it is inadvisable to move executable programme files. There is all sorts of configuration that was set at the installation of an application that may be incorrect after you move it. If you really wish to move applications it is probably best to uninstall and install elsewhere from scratch.
Moving data files and suchlike is easy. Open up a Windows Explorer of two and use the menu options 'cut' & 'paste'. Cut from the existing location, paste in the one you wish to move it to.
Virtual memory problems suggest you could do with still more real memory to stop Windows feeling the need to move stuff to the virtual memory file on the hard disk. If you are not comfortable with that sort of upgrade ask a knowledgeable friend to recommend the memory for your PC, open it up, and install it.
If you want to enlarge the virtual memory file though, then that can be done using the virtual memory settings. It varies from PC to PC but on mine it's settings/control [panel/system/Advanced/performance settings/advanced/virtual memory change. But again I'd advise getting a knowledgeable friend to advise at your side.