AD, okay, take it from an old dude, you can do anything on a computer that needs to be done.  Today's computers are not your mom's computer.  They are made for those of us who want to save money on repairs.  Heck, I built my first computer when I was over 60.

I will tell you true, you can have problems with any brand of computer or component.  There is no such thing as a perfectly problem-free electronic device.  However, I have been helping on these forums since 2002.  I have recommended HP computers to three family members in the past 1-1/2 years, two desktops and one laptop/notebook.  They are all very pleased with their purchases and have had no problems that they didn't cause themselves.

One of the biggest assets of buying a HP computer is this forum.  We have taught members, who no doubt know less than you, how to change hard drives, video cards, memory and power supply units (PSU).  These are the most common components.

I agree with your choice of AMD CPU's.  I believe that Intel may be a bit faster right now, but AMD still is considerably less money.  The only way that you will notice the difference in speed is if you do benchmarks.  Your eyes can't see the difference.

Yes, the pre-built computers come completely assembled.  The most that you will have to do is connect the monitor.  I highly suggest buying one that has Win7 already installed.  It seems to be far better than Vista.

Before you buy, give allot of thought to how you will be using the computer.  If price is the only reason for buying it, you may be sorry later.  A few dollars more now, can save you a few more dollars later.  If you will let us know what you want to do with it, we will do our best to help you buy one that will make you happy for a long while.  Find the computer and provide a link to it.  We will review it to give you some pointers.

Good luck!

AD, the configuration that you have listed makes a very good gamer.  The only change that I would suggest is upgrading to the ATI HD4850.  You can never have enough video card.  To offset that additional cost, don't buy Norton.  There are FREE programs that will do the same job better, such as, IOBIT 360.  This is what I use.  Oh, maybe one more upgrade.  I would go with the Phenom ll 810 or 925.  This will save an upgrade later and probably some money.

If it were me, I would stay with HP.  This forum is one of the biggest assets of owning a HP computer.  Acer (can I say that  :smileywink ) is an okay computer, but I don't believe that they compare to HP.  I have three family members who bought HP computers, in the past year, at my suggestion.  They are all extremely pleased with them.  They all came with Vista.  You would be a step ahead of them with Win7.  At least, so far, it seems to be leaps ahead.

Let us know if you have further questions.