How do I figure out if my laptop has hardware problems?

[Sixtrock]

Hi Ok my grandma got a new desktop a few weeks ago, it came with a free trial of McAfee which I installed for her no probs (have it myself at home) She already bought a different antivirus package (Bulldog?) which I was going to install when the McAfee trial was up. Anyway my little brother has been up for xmas and since there's only a few days of the McAfee trial left thought he would install it now for her. Since then the pc goes on to the desktop and thats about it, it wont let me open anything in the controll panel and cant get on the internet. It wont even turn off so have to do it by the button! Its as if its loading up constantly but doesnt do anything at all. I'm pretty sure it's cos of the 2 antivirus software together am I right? How do I sortr it? I wanted to go into add/remove programmes and get rid of McAfee but I cant get into it? Thanks for any advice parenting tips how to stop procrastinating stress reduction the power of your subconscious mind daily motivation improve concentration overcome shyness