ssd clean install - i do not want to migrate my old drive

i'm trying to do a clean install from usb with windows7 ultimate x64 onto a Samsung 840EVO 250gb SSD. i've tried this on my tower pc and i've also tried the 840evo ssd in my laptop, both systems recognize the ssd but when i click on format the ssd is showing as the primary drive but it then say no partions can be found and so i can't go any further with install - i've got it set to ahci in the bios. does anyone know where i'm going wrong and why it won't let me do a clean install

i found out my card reader was at fault. i put my micro-sd card into another reader and it all installed without a hitch

i didn't think i had to as its a clean win7 install. i've just read that link and it says this:

Situation

If you install Windows7 on a brand new SSD, you need not make any special arrangements because the Windows7 installer will do the alignment for you. For Vista you are lucky because the start sector happens to match a SSD page. For XP the start sector is 126 which would be in the middle of a SSD page, thus a prior alignment is required.
A similar situation is present when you clone an existing OS (including Windows7) on a new SSD.

not yet but i will in the morning. thanks for that link