Question Laptop wont go past black screen with blinking underscore....not getting grub menu too...need Help


Sep 8, 2016
Hi, I'm using Inspiron 3521 I3 2365M laptop

It has a single 500Gb hdd drive and I had configured it for dual boot. I was using both Windows 10 and Ubuntu on separate partitions.

It used to ask after boot to Select for starting a particular OS (through grub menu).

I wanted to install windows 7 in windows 10 drive and made a windows 7 bootable usb.

When I tried to select Windows 10 partition during Win7 installation........GPT Error was occuring. (Partition needs to GPT for installing win7 on a partition)

So I searched online about it and downloaded "gpt fdisk" (

actually I was following this tut and did same stuff for win10 partition. (

here are exact steps which I did according to above tut:-

1) extract gpt fdisk contents to the root of your BOOTABLE WINDOWS USB / DVD

2) Now boot up your USB only in UEFI MODE

3) Proceed installation as usual until you see disk partitioning step.

4) Now press Shift + F10 which will bring up a command prompt

5) Now type "notepad" and hit enter

6) Go to "FILE" & Click on "SAVE AS", then click on "THIS PC" and select "ALL FIles" from the "save as type" drop-down menu

7) Now go inside your bootable USB or DVD and you'll see both 32 and 64 bit version of GDISK. if you are installing 32 bit windows then use 32 bit version & if you are installing 64 bit windows then use 64 bit version.

8) Just right click the file and select "run as administrator"

9) Now just type the disk number of the disk which you want to convert for E.x If you want to convert disk 0 then type 0: & hit enter, If you want to convert disk 1 then type 1: & hit enter, If you want to convert disk 2 then type 2: & hit enter and so on

10) Now type "Y" & hit enter

11) Now type "t" & hit enter

12) Now just type the partition number of system partition & hit enter

13) Now type "EF00" & hit enter

After these steps, error was occuring like "this is efi based partition"

Whenever I restart laptop and start win7 installation, it just get stuck at win7 logo......It doesn't go further.

However if I remove bootable usb......I see blinking Underscore with black screen after dell loading screen everytime.....

There is no Grub menu to choose an OS after dell loading screen.......

So what should I do now.......I have important data in a partition. ( Not talking about os partition ).

Note : I have access to "Setup" Bios......and "Boot Options" in start at dell loading screen.
Apr 12, 2020
Can you try to repair Grub menu first. Dowload Boot Repair Disk and make a bootable USB. You can use Rufus to make bootable USB. Then boot Boot Repair Disk with using Boot Options and select Recommended Repair.

Restart your computer and see your Grub is back or not