You could attach code to the control's On Mouse Move event to open the second form, but then the focus would then shift to the new form instead of staying on the original control, making it difficult to know when it was time to close the second form. If you open the second form as a dialog box, you could use the On Mouse Move event to open the form and then the user would need to close the form manually.
If you just want to display text when the user mouses over a control, you can enter the text in the control's ControlTipText property.
Regards,
Lisa