So i would want to wipe my HDD so i could install windows 7 on it. But im not really sure how to do that and what software should i use, i've hear that DBAN is pretty good but is there any other good free software?
Do you have more than one HDD installed in the system?
i have 2 hdd .1 boot drive 1 storage drive
Use gparted on a live linux distro. You download a linux distro of your choice, burn it on a DVD, boot from the DVD (that doesn't install linux, just runs it), then use gparted to delete the partitions on and reformat the drive you want. Don't worry, linux can format NTFS, the archaic windows filesystem, as well as pretty much any other filesystem out there.
I you continue to use Windows (and it's not like gamers have a choice lol), you should always keep a linux liveCD or liveUSB handy to fix problems with windows, like scanning for malware or fixing partitions or any number of other stuff.
I use killdisk http://www.killdisk.com/downloadfree.htm
Have used it several times, works very well and efficiently
You can just use the Windows installer. When it asks you to select the drive just delete the existing partitions.
Data can still be retrieved from the drive though, however, I don't believe your intentions are to completely remove all data from the drive in a way that it is unrecoverable.