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I have a laptop that has Windows 7 64 bit Enterprise edition. It is already filled with plenty of Software and drivers.

The laptop (Dell E6220) supports booting through UEFI, but the insatllition was on legacy BIOS.

When I try to change the booting from Legacy to UEFI I get an error message that no boot device was found (the Windows 7 doesn't recognize as bootable). Is there any way I can configure the current install to allow booting from UEFI or do I have to format and reinstall?

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up vote 5 down vote accepted

Windows 7 on UEFI requires that the disk partitions use GUID partition table (GPT) rather than the traditional MBR partitioning format found on BIOS systems. Unfortunately, windows provides no way of converting an MBR partition to a GPT one non-destructively. However, if you don't mind copying data off your drive, converting, then copying it back then you could use windows to do it as described here.

If you don't want to backup the data first and have access to a a linux machine that you can install the drive in, there are tools in linux that will allow you to convert the partition type non-destructively as described here. If you don't have a linux box handy, you can also try creating a linux boot CD and booting from that.

Searhing for "convert MBR to GPT" brings up other tools, but I have never tried them.

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