recovering data from a formated hard disk

Clarifications

Any temp files written to that drive are just going to make things worse as they're overwriting your data.
There are several commercial software products available for data recovery. I can't vouch for how well any of them work. What you'd need to do would be to take the hard drive out, put it into a USB drive caddy. Load the recovery softwaare on another computer and see if your data can be recovered.
I'll break the news to you, don't have too much hope that it's going to recover all or any of your files.
I've recovered pictures from a flash memory card before but that didn't have data written over top of it. Your case is going to be a matter of luck.
There are data recover specialists that might be able to recover your data. I can't name the best one but from what I hear the prices range into the thousands of dollars. I hear that it's hundreds of dollars just for them to evaluate your drive.
Good luck. The next time maybe you should backup your data to an online storage service, CD, DVD, UFD or external USB drive.
Recover data: http://tinyurl.com/ykwr9sx
Backup strategies: http://tinyurl.com/yh8rq9t
Data recovery specialists: http://tinyurl.com/ycp4zk5
I'm not trying to be harsh but you've no ides how many times I've heard that someone lost "invaluable" or "irreplaceable" data. If it's invaluable why weren't copies made to store in a firesafe and offsite? It doesn't hurt to have backups of backups either. Twenty bucks buys a spindle full of DVDs.
I've lost data. I have backups now.

If this data is Important remove the HDD pack it up and send it to a Specialist Forensic Data Recovery Company.

As stated above the more that you use this drive the less likely you are to get a successful recovery and the more expensive the attempt will be.

If the drive was formatted during the install you can only use Forensic Recovery methods as the data has been overwritten and this isn't cheap. Either in the Pay for Service or the Specialist Software available both options are expensive.

Here you should have some form of Data Backup as the likelihood of loosing Data is way too great particularly with Note Books which get picked up and walked away with. If you don't have a working Disaster Recovery Plan in place you are going to loose your Data and that has to be expected.

Here I would suggest buying another HDD fitting it to your NB and reloading the system while the Original Drive is away being recovered. After it is returned you can fit the original Drive to a external USB Enclosure like one of these

http://www.xpcgear.com/ok250au2sk.html

And use it to backup your Data. If you want to attempt to recovery this Data yourself you'll need to replace the HDD in you NB and buy one of these enclosures though I personally would recommend an Actively Cooled Enclosure like the MX1 from Antec

http://www.antec.com/Believe_it/product.php?id=NDc=

Then fit your Original NB Drive to this enclosure and load your Preferred OS to the new drive which you'll need to fit to your NB. Then run one of the available Forensic Recovery Programs and save any recovered Data to the NB's HDD [b]Never write to the Drive that you are attempting to recover Data from.[/b]

Here is some idea of what is involved and On Track is one of the best Companies around for this type of work outside the Criminal Justice System.

http://www.krollontrack.co.uk/

Here is a small/short list of some Forensic Recovery Tools

http://www.cnwrecovery.com/html/forensic_dr.html

http://www.x-ways.net/forensics/index-m.html

http://www.toolsthatwork.com/computer-forensic.htm

http://www.ontrackdatarecovery.com.au/file-recovery-software/

There are other piece of software but I have no idea of how well that may work.

Depending on how much this drive has been used since the format and how big it is, as well as how fast the computer that it is connected to is, it can take up to 2 weeks to run the software. You can not stop and start the application that you use will have to run it's course till it has finished.

Col

but again, if it is really important, don't do it yourself.

You'll need to run the repair software from a live CD, or slave the drive into another machine.

But are you sure you formatted it? What exactly did you do, step-by-step?

I don't know how you'd accidentally format a drive, and people use the term incorrectly all the time, is why I ask.

If you installed Windows over Windows, look in the Documents & settings tree for your old profile folder, or possibly a windows.old folder in the C: directory.