Hi, Hope somebody can help.

I recently drew up a house and used a DWG as the template to help me position opening for windows, doors, and the roof. I do believe that the imported drawing was maybe corrupt. Anyway got rid of it but still believe that there must be some little insect left behind on Layer 1. The house is built but when trying to zoom in and out the model just disappears and is then found as the tiniest little thing so far away. Very difficult to get it back and once zoomed in it then just disappears again. Hope somebody can help in this pain staking issue of mine. Why is it doing this?

Thanks
Alastair