You haven't given us any information about which computer you bought. Is it a "brand name" computer? It's probably Windows XP but does it have Service Pack 2 installed? (RIGHT click on "My Computer", choose "Properties". Click on the "General" tab will tell you the EXACT operating system.
That said, if you read the User Manual and documentation that came with the computer, it will frequently tell you which programs are trial software. Sometimes, simply opening the software program will tell you. Most of the newer computers have the antivirus program, either Norton or McAfee as trial software, but you should check just to make sure.
And since you said: "Unnecessary programs", there may be a number of programs which aren't required even though they may not be "trial software". Compaq and HP put a lot of "junk" on their computers which can be removed...I suggest checking each program carefully and removing them one at a time. Having some patience in this regard is a good approach.
Hope this helps and let us know more.
Hi, I just bought a new computer. How would one know which software is trial software. I would like to get rid of unnecessary programs.