i downloaded a program and its a demo ,when i delete the program and downlod it again for use the program knows that i'v had it on there in the past. what file do i have to delete or what do i havre to do to completely delete the program???

Purchasing the program should make it work. :-)

Or format and re-install Windows. Most programs that have a trial period insert an entry into the registry somewhere that may have nothing at all to do with the program. So searching for related items doesn't work. If you like the program well enough to want to use it beyond the trial period you should buy it. If you didn't get a chance to really evaluate the program for some reason and still wish to do so email them and they may allow a second trial period.

... or reformat the hard drive to remove every traces of what was once installed or used, install XP then install the same shareware all over again. EDIT - I didn't see Othe's post when I posted mine. Been watching too much Obama-McCain politicizing on TV... i_Xp/VistaUser

"the program knows that i'v had it on there in the past." That's why it's called "DEMO"... Aegis is correct, if you've used the program past the "times-up" date, and you find it useful, then you should reward the authors of it for a useful product and buy it...