Which OS are you running? XP, Vista (if so what version), win7, or perhaps mac?
also, what are the specs of your laptop? (cpu, ram, hdd size)
If above is unattainable then what is the make and model?
if windows, can you open up task manager (ctrl+shift+esc, its faster than ctrl+alt+delete) and how many running processes do you have? is it running hot?
It could also be your power options. A laptop will typically hang when in power saver mode when it needs to access something from the hdd, essentially making the laptop useless while it spins the HDD up and gets what it needs.