BSOD, computer running poorly after hardware upgrades

Phoenix91357

Honorable
Aug 13, 2012
39
0
10,530
Before Christmas the computer was running great; after christmas an r9 295x2 was installed along with an 850w gold evga psu and new monitor (4k). The computer started running slower and the graphics card didn't make any different in games. So RMAing the card and monitor so the old graphics card r9 270x is back in the computer hooked up to the monitor (1920x1080 since it can't run 4k). The computer is still running like crap, it still has the new psu in it. I've ran malware and anti-virus scans (boot virus scans, safe mode scans, basically any scan I can), hard drive check. I'm not sure what it can be but it is irritating that it worked fine before all of this. Getting Internal Power Error BSOD. Games get laggy, freeze up and the computer slows to a crawl afterwards, restarting seems to fix it for a bit. I'm not sure what to do aside from a fresh install of windows and pray that works.

intel i5 3570k
gskill 8g ram
asrock z77 extreme 6
windows 7