There are a couple of solutions:
A) Buy a new harddisk and replace the old physically with the new one. Then install an operating system fully up2date. (Install a good firewall and anti-virus system too like Kaspersky, Symantec Norton 2010, or similar.)
If you're into computers, install Linux and configure it in a secure way.
B1) Your father may have installed a rootkit which does not get wiped by a regular Windows re-format. If you're not going for a new harddisk to be sure you don't got a hard2remove rootkit installed, get a "harddisk eraser" from IBAS or similar. (It's just a special magnet messing up the bits on the magnetic harddisk, in case it's not an SSD disc.)
B2) Perhaps, if there is a rootkit on your computer, a simple re-partitioning and format of the harddisk in Linux may erase everything. You can get LiveCD's in case you're not familiar with the linux console, and such a tool could be QTParted or GParted. I'm not sure how well Norton Partition Magic would work in this case.
B3) Do one of those Government Clearing of your harddisk where the data is wiped +5 times. (Depending on the method you choose, one of them will erase the data more than 30 times on your harddisk. It's a quite cool tool but I forgot the name unfortunately.)
C) Your father may have installed a rootkit in the BIOS, if so you need to replace the BIOS chip if possible. Otherwise buy a new motherboard or get a new computer. (Since it's a laptop, there isn't very much you can replace.)
Anyway, when you've done that and installed an Operating System do a FULL DISC ENCRYPTION!
Install TrueCrypt, and do a full disc encryption and set a good, long password with mixed upper and lower-case letters, numbers and symbols.
When you've done that set a password in the BIOS and make sure it is not possible to boot up on anything besides the harddisk. (Set the harddisk to be the first device in the boot order.)
Then you could set a password for booting up the computer as well.
There is however a reset jumper on most computers nowadays, which is able to reset the BIOS password. If you want to disable that functionality you need to do some hardware modifications to the motherboard in your laptop which I cannot recommend.
But if you follow most of what I wrote above, you'll be fine.
When you've installed your operating system and a firewall and an anti-viral system, don't visit websites your father suggests you
(He may be a rogue hacker too.)
Avoid using instant messaging programs except IRC.
Use HTTPS (ssl) whenever it is possible and encrypted protocols as well.
Now we're on the paranoid path, but depending on how well you want to hide everything from your father and anyone else, you're getting pretty close.
If you just want to confirm whether he's spying on you or not, do the following:
1. Set up a LAN where NAT is enabled. (A simple network with local ip-addresses, a router and another computer.)
2. Set up the second computer to log all communication from your computer to the Internet.
3. Don't use the laptop for anything but browse to a few websites you visit and then check the second computer if there's traffic that shouldn't be there.
This is NOT something that's easy, but it's fun
Good luck and have fun
PS: This reply was quite "brief" in how to do the above suggestions and these do not reflect my entire view on the possibilities on confirming whether your father has hacked your computer or not nor does it confirm how many ways there is to lock your computer down entirely. (In short, there's more to it than what I just said.)