See the change I made in your code:

>thank you for reply,
>i try it no result

if LEN(ALLTRIM(thisform.text25.value)) >= 3
lcFormValue = trim( Thisform.text25.Value )
THISFORM.TEXT10.Value=lcFormValue
WAIT

  for i=1 to 3
       cAlias = ICASE(i=1,'mstr2010',i=2,'mstr2001','mstr2011')
  text to cSQL noshow pretext 15 TEXTMERGE
SELECT no,img1 ,EXPBDATE,SDISC,STYPE,ansdisc,expbno from <<cAlias>> ;
WHERE ATC( "<<lcFormValue>>", SDISC ) > 0 ;
  INTO cursor TAliascursor1 readwrite
endtext
&cSQL
  **************************************
>  
>		thisform.Grid2.RecordSource=" TAliascursor1" 
>		IF i = 1 AND _Tally # 0  
>			  thisform.Grid2.RecordSource="TAliascursor1"
>			  thisform.grid2.visible=.t.
>			  thisform.grid2.enabled=.t.
>			  thisform.edit2.visible=.t.
>			 EXIT 
>		ENDIF 
>		IF i= 2 AND _Tally # 0  
>			   MESSAGEBOX("Found !!")
>			   thisform.Grid2.RecordSource="TAliascursor1"
>			  thisform.grid2.visible=.t.
>			  thisform.grid2.enabled=.t.
>			  thisform.edit2.visible=.t.
>			 EXIT 
>			 endif
>			 IF i= 3 AND _Tally # 0  
>			   MESSAGEBOX("Found !!")
>			   thisform.Grid2.RecordSource="TAliascursor1"
>			  thisform.grid2.visible=.t.
>			  thisform.grid2.enabled=.t.
>			  thisform.edit2.visible=.t.
>			 EXIT 	
>			 	
>		ELSE
>			   thisform.grid2.visible=.f.
>			  thisform.grid2.enabled=.f.
>			  thisform.edit2.visible=.f.
>			  * MESSAGEBOX("Not Found")
>		 ENDIF
>	NEXT 
>ENDIF
>
>
>

>>I would additionally textmerge your "thisform.text25.value" in the SQL-Select. When the SQL processes it is expecting queries based on a table.field basis. When you throw at it a thisform.text25.value it sometimes gets confused... You might want to change like
>>
>>lcFormValue = trim( Thisform.text25.Value )
>>
>>then in your WHERE,
>>
>>WHERE ATC( "{{lcFormValue}}", SDISC ) > 0
>>
>>(using curly brackets above for post... prevented from using angled brackets)