Hard drive interface is for a PATA EIDE 2.5" internal hard drive. Your original hard drive operates at 5400 rpm and so the largest hard drive I could find for your interface is 320GB
. You can use an an IDE Ultra ATA-100 or ATA-6 drive specification. You should plan to spend about $75.00 to $100.00 for a new laptop drive of that capacity. The largest ATA-6 drive I could find was 250GB.
You can find instructions for replacing your hard drive for the Gateway 4024GZ laptop here: