You want to remove the Citrix ICA Client (Receiver, Online Plugin – whatever the name is) from the Run-key for version 13.4 and below? That’s actually a bad idea – is it will break single-sign on due to a faulty repair in multiple versions of the client.
The Run-key is located here for a 64-bit version of Windows.
Citrix creates a String-value named ConnectionCenter that allows the ICA Client to startup during logon. If the value is removed – the ICA Client will initiate a repair that actually remove another registry key;
Once the above is wiped single-sign on is ruined.
A better way to proceed is to let the ConnectionCenter value be blank. That will avoid the repair from happening.