Currently I only 1 hard drive that holds, OS + everything else
I want an SSD to hold OS/games
When I switch to AHCI from IDE in the BIOS and clean install windows 7 onto the SSD, will the other drive, that will now be a secondary drive (with old windows files on it) be effected? Or will it work normally?
Also once I clean install windows 7 to the new SSD, can I delete everything on the HDD that I dont need (including old OS)?
Just back up everything in your personal folders you may not be able to access them later.
Also disconnect HDD when installing and reconnect later, that way you wont have to worry about setting disk priority etc.
Otherwise you shouldn't have any trouble at all the HDD will work normally and you can delete anything you don't need from the drive (including OS).