Sample code to close all browsers which are in open state through DP

Closing browsers through Descriptive Programming
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While Browser("CreationTime:=0").Exist
Browser("CreationTime:=0").Close
Wend


bIndex = 0 'Set Browser index to 0
While Browser("CreationTime:="&bIndex).Exist(1) 'Loop untill the last browser
bTitle = Browser("CreationTime:="&bIndex).GetROProperty("title") 'Get the browser title
If InStr(bTitle,"Google") = 0 And InStr(bTitle,"Yahoo") = 0 And InStr(bTitle,"Gmail") = 0 Then
Browser("CreationTime:="&bIndex).Close 'If the title doesn't contain Google or Gmail or Yahoo, close it
If bIndex <> 0 Then
bIndex = bIndex - 1 'If browser index is more than 0 and a browser is closed, decrease the index value by 1
End If
Else
bIndex = bIndex + 1 'If no browser is closed for certain run, increase the index value by 1
End If
Wend

Through Tool (QTP)
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Go to Tools-->Options-->Web

Here you can see an option "Ignore the following browsers" where you can add your required browser details which QTP will ignore during record/run.

Using HWND:
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Dim HWND: HWND = Browser( "title:=Google" ).GetROProperty( "HWND" )
SystemUtil.CloseProcessByHWND HWND

Using Process ID:
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PID = Browser("title:=Google").GetROProperty("process id")
SystemUtil.CloseProcessByID PID

Source: Internet