Can't re-try demo software

A few years ago I must've demo'd a bunch of diet software on my laptop. I really want to buy something now and of course all the demos have expired, but I can't reinstall them as something must be coded into my system saying they've already been on there. All I get is a screen saying my demo has expired and it give me a buy button. I can't figure out what to delete or edit on my machine in order to be able to pick one of them out to buy.

I know this is designed so that people won't keep extending trial software, but come on - I did this in early 2010!

Any ideas?

Thanks!

 

Thanks, but it's not the browser. I can download the demos just fine, I just can't install them.

I got around it by booting off the original internal drive on my G4. I had installed new drives in 2008 but left the old one in. I had apparently installed one of the packages prior to that, but it allowed me to run the new one whereas the laptop would not. Guess 5 years vs 2 made a difference - sheesh!

Not the best of situations but I'll have figured out which I want in a few days, I already have a pretty good idea.