Thank you both for your advice - that's really helpful.
In the meantime I have bought a memory stick to transfer files. I put it ion and transferred a folder, then got repeated messages saying something was wrong and that data may be lost. Yep - a whole folder of my work has disappeared. I am now scared to put anything else on it. Is this the stick or the mac. I am inclined to think the latter as nothing on it seems to work these days. How am I going to get my info onto the new computer?/??
Thanks