Sometimes, when I'm watching video (Hulu for example) in Firefox or Opera, the computer starts to freeze. The sound of the video continues, but the video freezes. I can't un-maximize the window, or drag it around. Everything else becomes very unresponsive, although the mouse works. Ctrl Alt Del does bring up the blue logon screen, but Task Manager takes literally minutes of waiting to open. Ending the firefox process does nothing. Selecting shutdown from the CAD menu starts the shutdown process, but then it goes to that black Windows Is Shutting Down screen and then freezes, forever.
When I turn off the power manually, the next boot up is going to result in one of the following:
1. "Detecting Primary Master Drive... Not found" on the very first BIOS screen
2. "BOOTMGR not found" when booting into windows
3. "Windows registry file is corrupt or missing" when booting into windows
Usually it fixes itself if I keep restarting the computer and/or leaving it alone for a bit and/or booting off a windows 7 USB and picking Repair. But this time, when I try to boot off the USB, it says the boot config data file does not contain a valid OS entry, and mentions boot/BCD. If I try to boot off my HDD, it shows the black screen with the logo that slowly comes together and "Windows" underneath it for about half a second (not enough time for the logo to come together of course) and then it gives #3 above.
I installed a HDD check program, it's been saying 100% health. On the other hand, when I connect an old HDD, it boots into windows fine.
Windows 7, everything up to date, E7400, HD 4850, 4GB RAM. The HDD is very new, had good reviews off newegg.