Hello hemis, you said when you bought your laptop, than there operating system was "Linux". Therefore, I think, your hardisk formatted as linux file system base. Windows file system and linux file system is totally different. So when you installed windows 7, at that time you format your c: drive. So widows seven only recognize your c: drive. Because window's seven recognize that file system. Please you format all of other partition on your hardisk by "NTFS" file system. To see your all of other partition go to "run" option and write "diskmgmt.msc" and then press enter. Here you see all of your hardisk partition. Now select drive and right click and then chose "format".
All the best.