I installed SP1 again today and finally got it to work, but now the "tools" tab (the one that has "Object Placement Tool" as an option) doesn't appear on the menu bar at the top of the screen. I have gotten it to show up before but now its gone! Does anyone have any ideas as to how to get it back? Thanks in advance!

Did you install the updates to the SDKs? IIRC, these need to be appropriate to the level of patching done to the sim.

Problem solved, I installed the SDK SP1A and everything's fixed (I had the SDK SP1 before.) Thanks for your help!