You will need to add the extension updates to support the Win7 platform and then update the platform codes for any existing Policies and Client Tasks.
The process can be found here:
We have to do this about 3 months ago and it was all pretty straight forward.
I ran the SQL query on the DB but it doesnt seem to have made a difference...
It says no rows were affected
So from the Knowledge Base EPO 4.5 is not affected by this.
I'm planning an upgrade to 4.5 anywho, so if that resolves it I'll wait for that.