Was that is the display settings>advanced? For lcds never go over 75htz. The older crts could go upto about 90htz if the card supported it. That's something to take note of to avoid raising them up too high again.
For seeing the defaults restored manually starting up the system restore feature from the safe mode /command prompt only option seen in the F8 boot menu will bring the system back to the way it is was before raising the refresh rate too far. Once at the command prompt simply type in
%systemroot%\system32\restore\rstrui.exe
Once you type that in the way you see it here simply press the return/enter to see the system restore prompt appear. From there you simply choose a day and time depending on the restore points available to bring the system before the cahnge was made. You will then likely see the default 60htz setting.