Problems after replacing power supply

[hellsbel]

Hi guys, it's me again with a bunch of questions.
A few days ago my power supply unit crashed, so I had to replace it. It works perfectly fine, but it has a light grey wire consisting of black, red and white smaller wires and it has a four-pin end, which doesnt seem to go anywhere (my old psu did not have this wire). It is my first contact with this kind of hardware and i am pretty puzzled about this.
After the death of the old psu my computer decided not to recognize devices in my usb ports. And as I have an external sound card it is a pain in my neck. The computer does show that there are usb root hubs and says they are working properly. My mouse has a red light and it is blinking as it should be, when i try to connect my mobile to the pc it shows like it is working, but no sign of the *kraft g* on *my computer*. Also, it does not show that my generic usb device as the sound card is connected. To sum up, I looked up about my connected usb devices and it showed the history and also said none of them are connected atm.

If you managed to read this awfully written piece (English obviously is not my native language and i am kind of in rage here) and understand the problems, here are the questions

1. What does this wire described in the first paragraph do?
2. Is it possible that some kind of virus/psu crashing disabled the usb ports somehow? How can I get my usb ports to work?

 

[Buckshot420]

Is it one of these?

[/IMG]

 

[hellsbel]

sorry, no. it is thinner and coloured light grey. i would take a picture for you, but apparently i am unable to connect my dslr usb cable to the pc.

i found out that the usb hubs are self-powered, so i guess solving the wire problem would not solve the usb problem.
computer says that everything in the usb area is working properly and having up to date drivers. nevertheless, it will not show when any of the devices are connected. am i missing something here?

 

[hellsbel]

Could the usb problem even be a hardware one, when the internet cable goes to the same device as two not-working usb ports and the internet is just fine?

 

[hellsbel]

I got another frightening idea- maybe the motherboard is dying. At first the sound card died a few months ago, then now the power supply and usb ports at the same time. It is a msi 848p neo-v, seems to be old enough though.
sounds possible?

 

[SNGX1275]

Yes, could be dying. In reading the thread I had suspected that when the PSU went out it also took out the USB portion of the motherboard.

I *know* you said Windows thinks the USB stuff is working fine, but Windows is pretty bad at detecting bad hardware. I've had many NICs die over the years and they all were 'ok' according to Windows.

 

[hellsbel]

I formatted the local disk yesterday and the computer is extremely slow, the screen goes blank once in while (also happened before the format and after the new psu for a couple a times) and a few minutes ago all i could see on the screen were weird large-pixel colours for a minute or so.

So is it time to count the last blessings?

edit: you must be right, the computer also claims that the onboard audio is perfectly fine and i messed around with it for a week before acknowledging that it was a lost cause.