Hey,  
i have been playing on SA:MP servers for a long time now, i had a break for 2 days, came back and opened  SA:MP client and tried to enter a server, it come up with these exact words in a little pop up box: 
___________________________________________________________________ 
Error: 
GTA: San Andreas executable not found. 
(C:\Program Files\rockstar games\GTA San Andreas\gta_sa.exe) 
Please locate it now 
                         [OK button here] 
____________________________________________________________________ 
So please can anyone help me, i have searched the computer with "Search" and not found gta_sa.exe  it seems to have deleted itself or something. 
is there any way i can download this one file again to play, or do i have to download GTA all over again or buy it. 
Thats really all, i might have missed a few things out but please ask questions and help.