Dell Studio 1535 Laptop keyboard not working correctly?

My Daughter has a six month old Dell Studio 1535 laptop which keeps having a faulty keyboard, whereby certain keys in the middle of the keyboard stop operating, e.g H G J N M B T Y U and the Soft keys Play FF RW and volume control keys at the top of the keyboard. Apparently the only way to rectify the problem is to keep repeatedly pressing one of the "F" numbered keys whilst booting up. This allows a system reset, but some of the "F" keys are not functioning. Anyone have any ideas wich key it is? Have tried F2 F8 and F12 to no avail. The integrated mouse also fails occasionally.