How to solve the mouse-frozen problem? Thanks.

Have a netbook without CD driver. Now the OS has trouble: mouse is frozen. I did:

1. Copy all contents of os disk which came with computer when purchasing to a flash memory.

2. Reboot computer in Removal device, i.e., flash memory

But the problem was not solved. And then,

I tried to click Set-Up icon in flash memory. The monitor shows to ask me to type into Product Key. And then, I contacted maker(Dell). I was told: if you did correct operation, Product Key is not necessary.

Any experts can give idea how recover my computer? Thanks in advance.