System Restore Incomplete Question

dfjama

I have problem with sytem restore unsuccesfull.
I have downloaded earlier an .exe file and when I run it , it automatically restarted my system, then I tried to restore my sytem on three different restore points:
1- Installed Adobe reader9 Sunday May 03, 2009
2- System Checkpoint on Saturday 02 May, 2009
3- Software Distribution Service 3.0 Friday 01, May 2009

All of them gave me Restoration Incomplete
Your computer cannot be restored to ..so.and...so..(date & time)
No changes has been made to choose another restore point, restart system restore point.

it is not only this occasion, I have the same issue with different circumstances, so beside system restore being turned onn by default is there anything else needed in order system is restored successfull......

Many Thanks