Any artifacts before Windows loads indicates a hardware problem. Squares or lines like in your screenshot are 9.9/10 times due to bad vram.

Overheated memory. You may be able to get into safe mode. If it works there, kill drivers and try normal OS boot. Remove heatsink, clean, reattach it, don't forget thermal paste and new thermal pads. If you can't renew thermal disipation ability, then: Modify VGA BIOS to have lower clock/higher voltage. Before you do so, you should test values with OC utility. Other thing to think about is your 400W PSU, it may have overheated too. - Is fan in it running? - Does it have clean dust filter or is unit dusty? - If you ar enot confident about health of your PSU get new one with new GA (you do not want to kill another one) Side note: Do not expect significant performance boost from new VGA, due to your old CPU. May be time for whole new rig.

Hi both, thanks a lot for your quick answers, much appreciated! Pill, I'm so glad you pointed out that it's most likely VRAM - I will confidently get a new gfx card soon. (A HD7770 or 7790 but I know it won't give me a huge difference) Fox, I might actually try the BIOS settings first then. Never had a single problem with the PC ever though, if I ran games on it for half a day even. Now it was just idling in Win, then I launched one mediocre game, only ran for 30 sec... before this happened. Yes the PSU is a problem... its fan died 6 months ago, then I was really worried but then never had the smallest performance drop so I left it.... bad decision. I don't know how big a PSU I should get though. The 7790 would be a needier one I guess.

A good quality 500W PSU is OK for a mid-range card. Where are you buying from and do u have a budget? P.S. - can u boot in safe mode?

Thanks - well I will visit a local pc shop (prices here are good as webshops' ) Budget-wise... I would choose a normal one, not pricy but not the cheapest. I cannot test safe mod till the afternoon, but then I will miss my chance to buy the card today. So I don't know if I should even try the safe mode things, I got carried away by the thought of the new VGA 😀

OK well u can list some models in your price range and we can tell u if they are junk or not....lol Btw that E8400 should overclock to 4Ghz without too much trouble....

Awesome! I saw two ones at my price range: Cooler Master RS500-PSAPJ3-IT 500W Chieftec 500W GPA-500S8 12cm with OEM iArena Didn't link them cuz it's a Hungarian webshop Really? Because I didn't dare to OC it really - I built it by parts but never gamed too much. I have an ASUS P5Q SE mobo, I'll look into how I can change all settings there

Awesome! I saw two ones at my price range: Cooler Master RS500-PSAPJ3-IT 500W Chieftec 500W GPA-500S8 12cm with OEM iArena Didn't link them cuz it's a Hungarian webshop Really? Because I didn't dare to OC it really - I built it by parts but never gamed too much. I have an ASUS P5Q SE mobo, I'll look into how I can change all settings there

You'll prob need a better cooler, like a CM Hyper 212 Evo. Btw those PSU's aren't very good....any others? Or maybe a link to site?

Hmm in this case I think I'll skip it for now, for the extra cost. Re PSUs, here is a webshop I would use: http://www.edigital.hu/Informatika/Tapegyseg/Aktiv-c1408.html FYI, about 10000 is what I'd spend on a PSU, much appreaciated!

Went through quite a few test and I would recommend: CORSAIR VS450 - CP-9020049-EU 450W - 10.900 Ft http://www.edigital.hu/Aktiv/CORSAIR__VS450_-_CP-9020049-EU_450W_tapegyseg-p345933.html - got good ratings in tests, low ripple - according to HWIS.C test at 500W it has 79% efficiency (they ended overload test there) - WHSC.C made overload test up to 570W where their unit kept 81% efficiency

I had the very same problem with my 4870, baked it and its been working just fine ever since. give baking a try. i take it your card is out of warranty so nothing to lose really.

Gather ye old aluminium foil for covering and a heat gun in circular motions over the chips. Oven method makes all your subsequent pizza's toxic, and there is also running the risk of having everything fall off the board, or bake to a crisp. 🙂 If it's the VRAM memory that's fried it likely wont work anyway to reflow the BGA solder but nothing to lose at this point.

Yeah doesn't hurt to try baking. I saved my 8800GTX using the oven trick.

Wow. First time I hear of this, I will google it. Yes warranty is not valid anymore + bought it in the UK so yeah no way I could utilize it. NEW Problem is .... I bought a 7770 and physically installed it. Installed latest official driver from ADM website. Happiness as BIOS+Win loaded without artifacts. Tested it with a game. However it felt slower than the 4850... knew something was not right. Checked CCC > Overdrive. Now, it should display real sensor data there right? Check this: http://snag.gy/OqPXv.jpg after this I enabled overdrive and left everything at the same settings seen there and hit Apply. THIS is when the nightmare started. I've been struggling with it for 2 hours. It froze the PC, had to hard reset, just like before... at next boot, Windows loaded the desktop and in 10 sec it froze again before I could open anything (Say, CCC to disable stuff). I did a clean driver uninstall, and installed it again. Did not help. Went to safe mode, tried to ran the installer to choose Uninstall - failed obviously. Somehow I did delete it and installed Now I installed the default driver that came with the CD (it's a Sapphire GHz OC edition). It installed CCC 13.1 too... So far it works okay, but I don't dare to touch the overclock settings now... Also in the PC shop I asked if I can take it back - said yes. However at home I noticed the packaging was already open - thought it was normal as it could be shown to someone etc... but now what if what I have is a used device...? I would never know... And one more thing... http://www.hellas.rs/slike/kablovi/Cable-IT-P0406.jpg My 4850 had a cable like this. The 7770 has only of those 4-pin ones. Don't know if it's normal. 😀...probably is. Any help please?

Overdrive shows 300mhz because that is the 2D clock speed, with CCC open you are in 2D mode. No need to touch Overdrive clocks..... 13.1 drivers are a bit buggy, try these http://forums.guru3d.com/showthread.php?t=379775

My 4850 had a cable like this. The 7770 has only of those 4-pin ones. Don't know if it's normal. 😀...probably is. Any help please?

It's OK.

Of course, I don't want to overclock it at all. I was only concerned because it was not showing the right clock speed. A game was running in the background, surely it should have made the clocks move somewhat... activity from 0 > 1% at least. Still, the others aren't fine, like temperature at 0°C. Unless it is known not to work

Install the new drivers from Guru3D AMD section and check out Afterburner's monitoring app - it can display clock speed onscreen. http://forums.guru3d.com/forumdisplay.php?f=55 So can Radeon Pro......http://forums.guru3d.com/showthread.php?t=373303

The latest I've found on Guru is Catalyst 13-4 driver which is the same I kept trying and trying - but just gave it a try nevertheless. Windows still freezes at the exact time it always does. (just after it loaded everything on the desktop +startup apps). I got it working once by running a small game ASAP after Win loaded - the system was fine up until I closed it. Then it froze 10 seconds afterwards.

The latest I've found on Guru is Catalyst 13-4 driver which is the same I kept trying and trying - but just gave it a try nevertheless. Windows still freezes at the exact time it always does. (just after it loaded everything on the desktop +startup apps). I got it working once by running a small game ASAP after Win loaded - the system was fine up until I closed it. Then it froze 10 seconds afterwards.

If you disable all startup items (CCleaner) does it still freeze up?

Yes thank you I downloaded CClearner and disabled CCC. Now it runs fine. I will test it more tomorrow. What does it mean though...? I cannot use CCC with my card?