Display problem in Dell Inspiron 1440

Dear All
I'm using Dell Inspiron 1440 Laptop for the past 1.5yrs. I bought with windows xp & converted to windows 7 professional.

But now I'm getting display problem like screen colour changes to blue & return to its original during working. I have tried all updates but still the problem pending .

Kindly give some solution for this problem

Regards
R.Balamurugan

If you could take a screenshot when the screen is blue, and if it wasn't blue it would rule out software problems.

I think it is a hardware porblem, but it would be the best to see a screenshot which you are sure that it was taken at the time when the screen was blue.