changed a program in prefetch ( dat to notepad), all files changed but no restore

i was investigating a file in prefetch that i wasn't sure about to try to figure out what it was. i changed the program type with the properties function to notepad ( after pressing the change button). all the files in the folder changed however . i thought i would be able to reverse this using the system restore , but as soon as i went to do this , the computer automatically set a restore point at that time ( this has happened once again since )eliminating previous restore points. in my naievity i thought i could delete the files in prefetch and they might come back in dat format , but no such luck , still stuck in notepad. i note there is an "always use the selected program to open...." thingy under the list of programs , but the switch button is in that ghost style thingy , so even if this was the solution (?) i cannot deactivate it. anyone help please?

 

The files in the prefetch folder are in pf format and not dat. They contain application information that is loaded to memory on startup to speed program execution.

Go to Control Panel, Folder Options, File Types tab and scroll down to the pf ending. Highlight it and click the Restore button.

Do the same with dat files if you need to.

 

thanks for the advice . it's fine up to the point where you say click restore . however ther is no restore button here. perhaps i am being an idiot so i hope i don't seem to be being rude. i really am something of a novice here. the only options available to me after highlighting are the buttons that exist on the file tab page. under the details for 'pf' extention it states it opens with notepad and the buttons available are change or advanced . where it says to change click advanced there are options for change icon , new , edit , remove or set default . if i have missed something obvious please spell it out as nothing seems obvious to me .
if i cannot change the files in prefetch from the notepad setting back to their original format , does this make any difference anyway?

 

There may be no Restore button if the file associations have been changed more than once.

It will probably cause no problems just to leave the association as it is.

Does clicking on a shortcut open Search now?

 

well i've not seen anything that states a shortcut , so what that is i don't know ( remember i am something of a computer moran). as far as no difference , things seem to have setteled down , it just seems the comp needs to go through processes once unless i do some clean up functions . that's so far anyway. but still thanks . i'd still prefer to reset it , so if anyone sees this and can figure out , well great , but otherwise hopefully things will stay ok ( i think i may have just jinxed myself). that will teach me to go messing.