I have a Sony Vaio PC with a pentium 4 running XP. The machine is about 3 years old. We run it with two user accounts, the thing is when switching from one account to another, you have to wait ages before you can start using anything while it seems to sort it self out. Should mention it has Symantec virus protection. Any ideas?
Well the symantec won't be doing it any good: you'll see performance improvements just by uninstalling it and putting AVG Free on as a replacement.
When you say "switching" the user accounts, do you mean by clicking on the "switch user" button? If so, try properly logging out of one user and then logging into the other one.