Compression

right click on your c:\ and goto properties. under the general tab look at the bottom and make sure the 'compress drive to save disk space' check box is dechecked.

I have checked that drive is not compressed.And this problem is in all the partitions.I have also formatted my c drive but that also didn't solved the problem.

when you open windows explorer, is the HD displayed in blue - denoting compression.
would you have installed any software that would be compressing the HD after the format.

The drives are not in blue color but some files are in blue color in my each drive the files compress it self and i have to uncompress them again and again my music files softwares videos everything compresses it self.i uncompress those files and after sometime(15to20 days) they compress again.I have checked all my drives and none of them is compressed.And i have not used any software to compress my files.

what process are you doing to uncompress these files?
a lot of video, picture and music files are compressed during the creation process, by whoever created it and using their choice of compressor. for example an AVI video clip can be created using no compression, but it's size would be gigibytes as supposed to megabytes.
post back with the file extensions of the compressed files.

Not a particular file type but each and every type of file is compressed.if there are 5 files in a folder then 2 or 3 of them are compressed.Only files are compressed not any drive or folder.

okay, so it isn't any particular file type that is compressed. so how do you know that they are compressed and what are you doing to uncompress them?

To disable compressed folders, go to Start > Run.

Copy/paste regsvr32 /u %windir%\system32\zipfldr.dll into the Run text box and click OK.

Reboot.