hWnd is not visible

[sushil_gupta]

I want to maximize explorer. When I am writing below code

Code:

hWnd = Browser("name:=.*PRS.*").GetROProperty("HWND")
Window("hwnd:=" & hWnd).Activate
window("hWnd:=" & hWnd).Maximize

I am getting error.
Object not visible Line (14):

Code:

"Window("hwnd:=" & hWnd).Activate".

in the second line
If I delete that line then error will come
The operation cannot be performed Line (14):

Code:

"Window("hWnd:=" & hWnd).Maximize".

I tried even the code below

Code:

hWnd = Browser("name:=.*PRS.*").Object.HWND
Window("hWnd:=" & hWnd).Maximize

But same error
Same code is working on other machine. Do I need to change some setting of my QTP? OR is it related to IE setting?