pc does not boot when I remove second sata drive


I have a pc with 2 sata drives and I want to remove the second one
but when I disconect it leaving only the one with windows 7 installed the pc does not boot
any suggestions please?
I tried easybcd with no luck
thank you
Look in Disk Management at the partition flags.
"system" is where all the boot files are.
That's probably the drive you're trying to remove.
If so. Use EasyBCD 2.0 > BCD Backup/repair > Change boot drive.
Point it to your W7 partition when it asks.
Change the BIOS to boot from the W7 HDD.
W7 should now be "system" "active" and "boot", and the other HDD removable.
now I can not delete the windows folders or format the above removable drive.
any suggestions?
I prefer to format it