I got your model. It is already quite “heavy”, Model Info->statistics shows almost a million edges. About 2/3 of those come from just four things you no doubt downloaded from the 3D Warehouse:
- Group#1348 (curtains) contains 196,934 edges
- Group#990 (grill, sink, and counter) contains 142,175 edges
- Vase_Flowers_22 contains 115,325 edges
- Extemporare standard table… contains 104,003 edges
This is why we always advise that you download from the warehouse into a separate model and examine the download for issues such as size and excessive detail, and either editto simplify or choose some other model, before placing it in your production model.
As @DaveR found, I also had no problem purging unused item from your model though it took a long time. I agree that likely you have simply overwhelmed your computer with this model.
Edit: I also noticed that you are not using tags appropriately in your model. All edges and faces should remain untagged; only groups and components should use tags. Tags do not prevent edges and faces from interacting with each other, even when set non-visible, and that can lead to strange and frustrating errors.