Hi Harry,
I have one doubt regarding your question.
Your data validation( with four options as you specified) is at A1, and you want row 1-23 to be hidden when you select Personal loan. In that case, your data validation cell will also be hidden!...so I have little disconnect here.
You have also not specified what should happen when you select car loan / business loan
Do you want to execute the hide/unhide operations in sheet2 while you have data validation at sheet1?
However, as of now, in the below file I have placed data validation at A1(sheet1), on selecting Personal loan, row 2-23 will be hidden. And on selecting Home loan rows 2-23 will unhide and 23 to 46 will be hidden.
you can adapt the technique to your suit..
Change the selection from drop down and hit "click me" text beside.
Link for sample file:
http://speedy.sh/Degjy/hide-unhide.xlsm
Kaushik