The quickest test is to remove some of the RAM, however it is more likely that you changed some of the drives cables and that the drives now appear in a different order.
As to the max RAM:
- Windows XP is normally limited to 4 GB. It will boot fine if you have more memory. It will just not use it. (Exception: If you enable PEA or if you have the very rare XP-64bit).
- Windows 7: If you have the 32 bit version it will also work, but only use up to 4 GB. There is no PEA option anymore. If you use the normal 64 bit version of win 7 then supports varies with the windows version. ( Starter: 8 GB / Home Basic: 8 GB / Home Premium: 16 GB / Professional: 192 GB / Enterprise: 192 GB / Ultimate: 192 GB )
- I am assuming your Fedora installation is 64 bit (if not why?). It should not have any problems with the memory at all. If you happen to have an ancient 32 bit installation of Fedora then it should work fine, allowing up to 4 GB with PEA turned off, or 64 GB with PEA turned on). It should also display how much RAM it is using during boot.
As to the drive order:
Try booting Fedora in single user mode.
- t the GRUB splash screen at boot time, press any key to enter the GRUB interactive menu.
- Select Fedora with the version of the kernel that you wish to boot and type a to append the line.
- Go to the end of the line and type single as a separate word (press the Spacebar and then type
single). Press Enter to exit edit mode.
If that works try mounting drives. Changes are that whatever partition was on /dev/sda2 is now at /dev/sdb2 or vice versa. That will confirm that some cables got reversed.
Do not try try to fix it here unless you want to change the setup for every OS. Instead correct the cabling.