problem with nero 5.5

Hi.

My problem is that when I click on Nero 5.5 it wont open and a windows
message stating that another programme is using imapi please close.
I close this in windows task manager and then try opening nero again. This
results in my system shutting down and re booting.
Windows states that it has recovered from a fatal error and cycle begins
again. I keep uninstalling and re installing but still the same problem.
I have not had any errors with nero 5.5 in the past with the same system.
Im using windows XP home with service pack 1 and all the updates.
The other cd burning software is in XP itself. I turned that off but still
the same problem. I also have the free real player installed that has some
burning software built in but I've never used that.
I tried nero 6 free demo and that worked but has now expired......
Any help to get nero working again would be appreciated