Wrong hard disc calculation of primary Hard drive

[ahmed-maldives]

I have a 250gb hard drive on my imac and all files including apps and user files take up only 70gb. but when i check with 'get info' it says the hard drive only has 20 gb unused. I have used omnisweep and whatsize and both says only 70gb is used. but 'get info' says i have used up 230gb with only 20gb unused. Pls help me be able to use the actual remaining space on my hard rive, thanks.

 

[tyr2]

Daft question but have you emptied your Trash?