GRUB doesnt detect USB?

[etrac2]

I have a corrupt file of Mint 14.1 installed onto my computer as the only OS( I really messed up ) When turning on my computer I get the GRUB boot menu automatically. I am offered 4 options which are the following:
Linux Mint 14 MATE 64-bit, 3.5.0-17-generic (/dev/sda1)
Linux Mint 14 MATE 64-bit, 3.5.0-17-generic (/dev/sda1) -- recovery mode
Memory test (memtest86+)
Memory test (memtest86+, serial console 115200)

The first option just takes me to a blank screen and the keyboard ceases to work
The Second goes through text that I am unable to scroll through and stops at a random point each time then just freezes
Both Memory tests get stuck at test 9 with almost 800 million errors.(So something is OBVIOUSLY really wrong)

I'm getting desperate and I have close to no experience with Linux. I assumed that I could install a fresh Version of Linux MINT from my USB stick rather than fixing the current one (which is impossible anyways because I can't open the Terminal) But the GRUB boot menu doesn't detect the USB so booting into a fresh installation isn't possible.

I have no idea what could be wrong, I've spent hours looking for possibilities and have found nothing. :/

Any help or ideas would be wonderful!

Thanks in advance

[grizzler]

But the GRUB boot menu doesn't detect the USB so booting into a fresh installation isn't possible.

The GRUB menu is never able to 'detect' anything. It has to be told. What you need is the BIOS boot menu that allows booting from USB. You should be able to get that on screen by pressing a function key very early during booting. Which key depends on your computer (I have one where it's F8, another has F10 and another I currently don't even know what it is...).

When you switch the computer on, does the screen show any text before the GRUB menu comes up? If so, which key to use for the boot menu should be displayed there. Otherwise check the documentation that came with the computer or try to find out about it through Google.

It's possible you need to change the BIOS boot order before you can boot from USB, as the harddisk may currently take precedence. Pressing another function key when the machine starts up should get you into the BIOS settings.

And of course your computer may not be able to boot from USB at all, but it would have to be pretty old for that.

[eanfrid]

Both Memory tests get stuck at test 9 with almost 800 million errors.(So something is OBVIOUSLY really wrong)

Very probably some kind of hardware failure happens.

1/ Are you overclocking anything on your computer ?
2/ How many RAM sticks on the mobo ? If more than 1, (shutdown the computer) unplug all of them except the first one and retry a memtest. Then test your RAM sticks 1 by 1 until you get good results.

[catweazel]

The Second goes through text that I am unable to scroll through and stops at a random point each time then just freezes
Both Memory tests get stuck at test 9 with almost 800 million errors.(So something is OBVIOUSLY really wrong)

It's highly likely you have dud RAM. If you have 4 sticks, take two out. If you have two sticks, take one out. You'll have to troubleshoot the problem by swapping RAM about and doing more tests.

As for the grand unified bootloader not detecting your USB drive, that's normal. You must tell your machine's BIOS to boot from the USB drive. How you do that depends entirely on your machine. For example,on mine I can either go into the BIOS or press a certain key to choose the boot device. However I advise you not to bother with this option until you've sorted your RAM out.