Software that asks for serial numbers and original disks are probably protected by copyright.

By attempting to install the software, you are trusting that the person who made the file is not a scammer, a virus carrier, an employee of the company who made the original software, (flooding the net with bogus copies), or an idiot who doesn't know what files need to be included (or who has simply mis-named the file). The odds of getting a good, clean copy of software via p-p filesharing are very low.