It does seem to be better - It was particularly slow at opening programs, saving files and playing videos - all definitely faster now and I can turn on my firewall which I couldn't do before! But this is what happened when I tried to clean it up before - it improved for a short while and then reverted, I'm worried this will happen again.
The updates still won't install - there are 68 and the updater just fails.
I'll get speedyfox...
Thanks so much for your help!