Yeah those drivers come with the newer SDK with is much worse for mining in my experience. Try to go back to SDK 2.5

Depends on your other components and also what PSU specifically it is. Please post your specs and exactly what PSU you have.

DONT USE SDK 2.6! I hope you're not anyway haha. But anyway awesome shit. Not sure about Windows 8 but sweet rig.

Need way more info. What motherboard, CPU, GPU, and PSU, etc do you have?

Plenty of people on the forum. They'll want escrow but you'll find good prices. Or there's always ebay 

Lol I wouldn't be surprised if you managed to lose money with free electricity!

I'm looking for around $400 or equivalent. I'll accept any method although I've never used escrow. I know I'm new here with no rep so I'm happy to accept any payment method.

Yes it's good now. Only mine with the Juniper, not your CPU.

The kernelanalyzer has nothing to do with mining. I honestly hadn't even heard of before. Any card is supported. There aren't any limitations in that sense. Now, assuming you have the Catalyst driver and SDK installed, it will work. The only thing I can think of is you aren't changing the drop down box to the GPU, the card isn't working properly and may be broken, or you didn't install the SDK properly. It would help if you had a picture of your guiminer on here for me to see. Also, don't mine with your CPU. You spend way more on electricity than you make in Bitcoins.

Another possibility is you have your monitor hooked up to the motherboard and you don't have a dummy plug on your 5750 so Windows isn't showing the GPU.

For the 5800 series I haven't had the best luck with sub 300 mem speeds. My cards are unstable below 300. I would suggest keeping them at 300 unless they run absolutely stable.

Install AMD SDK 2.5. Here is a link http://developer.amd.com/sdks/AMDAPPSDK/downloads/Pages/default.aspx. DO NOT download the link on this page. Scroll down to the bottom and click on Archive page. Should say this (For versions 1.4-beta and 2.01 - 2.5 of the AMD APP SDK, visit the Archive page) at the bottom. Then fill out survey and download version 2.5 for your operating system. If you download 2.6 on the first page you will get much slower hash rates.

Wow my bad! Thanks for catching that. Guess you guys should help out! I need to get some sleep haha

(I updated my list)

If you want a dedicated rig and cheap go with this:

Motherboard:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130591
or
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262 (if you want 3 PCI-E slots)

PSU:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151109 (best psu out there)
or
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151108 (if you really need to spend less money, however you'll be limited on expandability)

RAM:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820139924

CPU:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103888

CASE:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119197 (unless you don't want a case)

Also feel free to PM me or post here exactly what you need this computer for and I'll put together an exact parts list for your budget and needs.

Come on man, you gotta invest in a good power supply! Always single rail, and high quality. Then you never run into any problems. Also, DO NOT use pci-e adapters for long. In fact I tried adapters on one of my power supplies and it failed after an hour. You need to get a good PSU with enough connectors. However, very temporarily you should be fine but don't over clock at all and look for a new PSU.

The cards though should draw around 20-25 watts from the bus. As for total power usage and 6 pin power usage I'm not sure. There are plenty of 5850 power usage forums here though just look around. I would suggest you undervolt the cards (you'd be surprised how much less power they use) and underclock them until you can get a new PSU. This will insure no hiccups and more peace of mind.

And there should be no CPU instability because it shouldn't be used (unless you have the 100% usage bug). Just underclock that thing and go with option two and you'll be fine. Also what CPU do you have?

Need much more info on your hardware. Sounds like a power supply problem to me!

How much did you raise the voltage? Voltage increase to an extent won't hurt in the short run but since mining is usually 24/7 it can be bad in the long run and dramatically decrease the life of the card. I wouldn't suggest going much over stock voltage if you do 24/7. I personally don't go above stock voltage at all but its fine to increase voltage like 3% safely.

Hey I don't get it either but I would't be complaining 

Yeah sorry my computer autocorrected my undervolt to undervalue lol!

With that kind of electricity cost I would suggest overclocking that thing like crazy and setting your memory to 300 (ideal for 5850 in most cases)! You will also get better hash rates with 300 memory.

The price is starting to go back up on bitcoins and while a lot of people are jumping out of the game there are a lot of veteran miners still buying. If you already have a 5850 I would suggest going ahead and mining! You will make more than you spend in electricity (assuming you don't pay an absurd amount). I would also highly suggest downclocking the memory and undervaluing to save a lot of electricity and heat. You'd be surprised how much it can help  . Here's and compiled undervolting results link https://bitcointalk.org/index.php?topic=65997.0. There are also other posts about underclocking out there. If you need any of those links just ask. Best of luck!