|"PSU corsair vx 450w"|
That's okay if you're using onboard video or a modest to mid range video card in a mboard slot, but it may not have enough capacity for some video cards in a slot.
Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.
If you're a gamer...
In most if not all cases, the max capacity rating of the PS is an intermittent rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should have.
If you need to get a PS with more capacity, you can usually replace it with any decent quality standard sized standard ATX PS.
Check your SATA data cables. The connector on each end should "latch" into the socket on the drive and on the mboard, or on the drive controller card - it should not move when you merely brush your hand against it near the socket - if it does, mere vibration can cause a poor connection of it - use another SATA data cable that does "latch", or tape the connector in place.
(There is a slight projection or bump on one side of the outside of the connector that "latches" it into the socket - it's easily broken off or damaged)
The same thing applies for the SATA power connection.
Look at Device Manager to see if anything is flagged with a yellow ! or a red X, and to see whether there any devices listed as Unknown or not having the drivers installed for them.
(E.g. double click on Computer - click on System Properties in the top bar, the link to Device Manager is on the left.)
If any of the locations you have the data on or that you're copying to or from are on an external hard drive or are on something connected to the computer via a USB or firewire connection, the max data transfer rate is MUCH slower than it is compared to copying data from one internal hard drive partition to another internal hard drive partition