I have posted this topic on the Malware forum (Am I infected?) and after identifying some infections, was advised to post here. My machine slows down to a dead halt, with system message saying 'low on memory'. At the same time I have to hard boot the laptop and start again, usually with the same results.
As imagined I cannot run more than one application at the same time and even then with inevitable end results.
Many thanks for your help,