Computer Keeps Freezing After Loading?

I recently built a new computer and only had 2 SATA cables, so I had my SSD and HDD plugged in.  This morning I went to plug my dvdrom in. I realized my HDD was plugged into a SATA2 port so I switched it to the SATA3, and plugged the dvdrom into the SATA2 port. I was always told it isn't a problem. A few hours later. I get bluescreened (happens every couple of days). But then I get a disk read error ~20 min later... I don't know if it matters, but then my main program crashes ~15 min later. After reloading it, ~15 later again, I get thick vertical *fuzzy plaid-like* lines and comp freezes. Restarted and now I'm experiencing where my computer freezes within a minute or two,with those huge vertical block lines. (I've seen similar when someone overclocked their GPU too high) I am not even running apps, just turning it on and this happens... Haven't done updates in several days. System is in my sig. I didn't build it, my tech-savvy friend installed everything. Windows 7 64-bit.