No more space on my hard drive

Hello,

my pc has 144GB hard drive, but it keeps telling me it is full and that I have no disc space left. I cannot believe that I have no space left. I am on XP have deleted all my photos, music and everything, but still no luck. I am told that given that I only use this for word processing and excel files, skype and email I should not have used up this amount of space. I appears that I have some unnecessary Program files on here - for example I have windows NT; WebIQ; Viewpoint; microsoft silverlight microsoft sync framework. Are these taking up my disc space? I cannot believe how I can have used all this space up.

Should I just take it in to a computer shop and get them to look at it?

Thanks I need help

Sytuppenny