Windows 7 Can't boot my pc in safe or normal mode. Just black screen with a _ blinking in the left upper corne

Are you running the system in UEFI?

A blinking cursor like that usually means the system is being directed to a non-existent or corrupted OS install.

If you have the Windows 7 Install DVD, try booting to it, and doing a Repair-Startup Repair.

But in the bios, what does it say you are attempting to boot to? Can you get the boot device menu with F8 or F5 and make sure you are booting to the Windows Boot Manger, or the Hard drive with the Windows 7 System partition?

I tried the windows 7 installation disc, weird thing is that it doesn't detect my OS... And yes, I'm sure that I'm booting from the right system partition..

If the boot files have been corrupted, the repair will not recognize the install. You can try to continue by selecting the repair and see what happens.

If you have Windows 8 running, can you get us a snipping tool picture of the Disk Management window and attach using the paperclip?

I don't know exactly what happen, I started the pc again, and I had forgot to take out the Windows 7 disc, I booted it up in windows 8, but instead of the login screen it asked me, if I wanted to boot from the windows 7 (Recovery) or windows 8, I tried to pick the "windows 7 (recovery) and it shut down, when I booted it again, I tried to run it from windows 7 and it started to run all kind of check ups like CHKDSK, etc by itself. When it was done it rebooted by itself and began agian. It took almost 30 min, and suddenly it was on the windows 7 logon screen, I tried to log in which worked perfectly, and as soon as I got on the windows 7 on my user, it worked kind of usual, other than my entire E: disc was formated cause I had had to install windows 8 on it, and the screen was black, the menu start was completly empty, I couldn't pick computer, control panel, documents, or anything, the windows bar in the bottom was messed up too, and my anti-virus whent rampage about 7 viruses or so. I don't know exactly what happen, but read carefully the virus descriptions, seemed like nothing dangerous, so I let the anti-virus delete them without further notice. I had to all my settings back, but when that was done, everything (execpt the missing files) were back to normal. Well, there is still 2 abornormalities, the first is that my internet explorer doesn't work, as soon as I start it, it loads up, and I go any kind of website, and it chokes, I got my friend to send me Firefox by skype, so that issue isn't that big. But the other things that happen is that, once everytime it's been started up, the pc COMPLETLY chokes for about 1-5 minutes, it usual happens when I install something, which is annoying, and nothing works on it, when i press stuff like ALT+CRLT+DELETE it either does nothing, or the screen turns the usual way, but instead of a menu it says "Preparing security options" until the choke is over, if it ever is. I tried that I had to reboot the pc 2 times following after it had happen. It's very odd, but it's possible to live with, I might post a new thread about it later to see if it's possible to fix, and when I know more about it. But thanks for everyones help, I really appreciate it. :=) Thanks everyone.

I'm suspicious that you might have gotten some malware when you clicked yes on the popup. I learned to use the task manager to close strange popups asking to install something. Once I tried to close a fake AV one by clicking the red X and it started loading. If you can get Windows 8 to run download MBAM and scan the Windows 7 partition. Also do a AV scan of it from Windows 8. MS also has an AV app that you burn to CD and boot from that, it might be worth a try.
Joe