PSU can be defective no matter the wattage and random spikes can shutdown your computer. A different harddrive may cause those spikes it also might be broken (the HDD) I once had one that randomly renamed folders and files into  crap like 4&$(/)"$)=(=$")($  other than that it worked perfectly fine.




@OP

Try using another SATA port on your mainboard and try another cable too.

Also  what browsers do you use? Chrome might be the problem.  Try using another browser and if nothing crashes then you know its chrome. Try disabling the built-in  Flash "plugin"



Fire up Chrome and type about:plugins into the address bar then hit enter.
Click on Details in the top right of the window to expand the plug-in details.
Find the Flash plug-in that's listed as being in the Chrome directory and hit Disable.
Use the standalone flash player that you can download at the adobe site instead. (its not as slick tho)

My 1st reaction was you have an issue with your PSU
2nd reaction was your video card has driver issues
3rd reaction is you tried to OC and you have stability issues.

its (most of the time) not the PSU if the system is running fine with another HDD.

its a HDD  or softwareproblem,HDD,  windows 7, drivers, browser or flash.

1. check with another browser(he reinstalled flash i guess), use firefox and chrome for the test, naked versions from the offizial site

2. if that doesnt make a difference, update drivers

3. if that doesnt make a difference, install windows 7 on the windows 8 hdd and test again.

4. if that doesnt make a difference, well thats a real problem. a working but broken psu is hard to test.

and use the same cables everytime u test the windows 8 vs windows 7 hdd. u can test other cable combinations, but make sure u test em with both HDDs.

5. if u can live with windows 8, just use windows 8 and both HDDs, that should be a working workaround if u cant find the error.

I'd check the ram. Use Memtest. I've had hellish PC problems where it randomly do shit. No matter the time. I expected other things. When a RAM stick/slot went dead. Do this to rule them out.

Have you checked all the connectors?
Also, if Windows 7 was directly put in the new PC already installed on the HDD, did it perchance previously run on a system with 2 HDDs? In that case check whether some important files and directories weren't in default positions but customised (for example, I always put the swap file in a dedicated partition, to prevent it from drastically increase fragmentation of OS, programs and data partitions): if some of them were on a different HDD, and the new system just uses one of them, it could cause errors (although in this case, if the OS can start at all, it should show you an error message when the failure happens).

But.... porn... my lovely daily porn...

Is it a strange question from me if i asked: Why don't you just run Win 8?

ram errors look different most of the times, but u are right, a broken ram can cause the wierdest of all bugs. had realy funny problems at university with a broken ram...

I had crazy shit. Like I could play a game for 10 hours nothing would go wrong. I play another game later on. My PC would freeze after 1 minute. Flash would comonly hard crash (no blue screen) my PC that had the defective RAM slot. Even iTunes would lock up my PC. And I used that Ram stick/slot for 2 years. Before it fully failed. And wouldn't let my PC go past boot check.

So, flash based software causes crashes in Win 7. Have you tested flash in Win 8?
There are some websites that install flash players with viruses.