I have installed Open susi on my laptop and with the first restart I got the following message.

Welcome to GRUB
Attempting to decrypt master key
Enter passphrase for hd0,gpt4 ( lots of numbers here )

What do I do now ?

Did you encrypt the disk when you did the install? If you did then you will need to enter the pass phrase that was used to do the encryption.

No, I didnt encrypt the disk and as the PC is waiting for a response from me I tried my name and password.I also typed in Windows and Linux,none of which worked.There is a flashing cursor ( like you get with a DOS prompt )so it is obviously waiting for a response from me,but I havent a clue what to type in.

If I restart thr PC and ESC and the Windows key,I get the following message:
minimal BASH - like line editing is supported.For the first word,TAB lists possable command completions.Anywhere else TAB lists possable device or file completions.

Is this any help ?

This seems to indicate the disk was encrypted during install. Maybe you checked the box but did not enter a pass phrase so it may be empty. Have you tried just <enter>?

If that does not work then I have no further suggestions. Maybe a reinstall?

yes, I can only suggest you to reinstall and avoid using encrypted drives next time (if that enter did not help).

Lucky for you there is no real loss on reload.

Not sure what you typed in. Try either your user name, user, or password but not all at one time just to see if you can get past it.

If fails then I agree with others, reload it and be careful when it asks questions. Some questions may be very slow on older hardware so be sure you wait a bit on screens maybe.

I have just had a rethink of my problem and I am sure that what I have to do now is get back into windows,format the Linux partition and install a different version of Linux.
Can anyone please tell me how to get back to windows ?
The reason I have come to this conclusion is really quite simple.I installed Open SUSI beside my Windows after partitioning the HDD.The thing is that on startup surely I shoul get the option to select Windows or Open SUSI ?! I dont get this option ( as mentioned in my first post ) I go streight to the encrypted Linux HDD.Which leads me to the conclusion that the Open SUSI disk was/is corrupted.Which also makes me realise that I did not encrypt the HDD the program did this all by itself.Why would I want/need to encrypt the HDD ? I am the only one that uses my PC.

when you boot (switch on the computer) it will ask if you want to use windows or linux. But probably you have overwritten your windows so it is not available any more.

I am quite sure that I have not overwritten Windows because before installing Linux.I partitioned my HDD and installed Linux in the F partition.So the other partitions should ( C Drive with Windows and D Drive with the recovery )I am quite sure that the corrupted disk has encrypted the F partition and probably stuffed up the MBR.I need to get back into Windows,if possable or failing that I could use a Linux Live DVD and format drive D.
If I use a live DVD will F partition still be F partition in the live DVD of Linux or will there be a different drive number.As I said I have C = Windows D = Recovery and F = Open SUSI.and what is the command to format this partition from a Linux live DVD ?

in that case you need a partition editor and select the one you want to boot. Or probably you need a windows recovery solution to be able to boot that again.

Linux does NOT see the drive C, drive D, etc. naming that windows uses. It sees the partitions on the device. Assuming the drive is /dev/sda then it sees the partitions as /dev/sda1, /dev/sda2, etc. That means your referring to drive F is totally off base and cannot be directly related to the partition you created for linux.

Before you do anything else please post the output of these 2 commands so we can actually see what has been done with the drive and if windows may be recoverable.
This can be done when booted to the live USB or DVD that you used to install. Once we have looked at that we will be better able to provide accurate advice.

Windows does not assign drive letters to Linux partitions so if you tried to install it on what you see as the 'F' drive, that is likely and ntfs or other windows filesystem and that won't work. Use unallocated space.

You haven't indicated whether you are using UEFI or a Legacy/CSM install of Opensuse or windows. Which is it? Also, it would be useful if you indicated which version of windows you are using.

I've never encountered any Linux installer incapable of formatting a partition as an integral part of the installation process. Some even demand to do it before proceeding. openSUSE's expert partitioner in its installer will do virtually anything one would ever want of a Gnu Linux installer. Thus, there is no point in "formatting" anything to be used by openSUSE in advance of installing it. The same goes for partitioning.

Your openSUSE installer almost certainly wiped out the MBR code that Windows requires to be able to boot in the absence of a working non-Windows bootloader. openSUSE would have put Grub2 in that space. A Windows recovery and repair disc or USB stick can put the required code back in the MBR. However, a subsequent Linux installation will by default usurp it again unless steps are taken to install its bootloader elsewhere. All my installations boot the bootloader on a partition, so that the MBR contains only legacy/Windows-compatible code. With such configuration, any time Windows breaks Linux bootability is normally just because it moved the MBR boot flag legacy code depends on. This flag is easily moved regardless what is bootable or booted.

No Linux distro has any conception of drive letters. The partitions with filesystems to be used in Linux become directories or subdirectories, whether Linux native or not. When requesting help with partitioning with Linux you need to provide a partitions list at the minimum instead of referring too drive C: or Drive F:. This list is the output from fdisk -l or parted -l or equivalent.

There are ways to fix it.

One is to use Microsoft Windows to fix the loader. Common for people who want to return to stock. Free iso's Microsoft.

Two is to use some built in recovery if you have it to basically do what a Windows dvd might do but could do much more to return the entire system to as bought.

You do have a backup of your data right?

Three is to use linux to try to fix what you have. Some linux installers may "see" the Opensuse and not easily let you copy over it but that is a new thread.

Next time consider a free "Virtual Machine" to use windows and linux at the same time. Much safer than a dual boot.