my pc will Not download! please help!

hi, I have a compaq presario that my aunt gave me. She always said she had problems with it, tho she always blamed herself (I guess I did too lol) anyway, it goes to websites with no problem, but it will not at all download anything. I have checked my settings, everything seems to be like my prior pc as far as that goes. the computer says it is downloading, but it goes to a blank white screen usually when done. I decided to try to download yahoo messenger. I got an error reading saying that microsoft inexplorer can not open this, operation aborted. I tried pirch, I tried firefox, I tried explorer 7. All of these did not download. Anyone at all that can help me has my thanks. feel free to email me anything that will help me!