So you're thinking about a new PC

First let me tell you my decision making method for my own computers. I expect 3 years service out of a computer (& basically spend whatever is needed to keep it running for those 3 years if anything does go wrong). After that I'm looking for an excuse to change it (e.g. it wont run a program or game, it'd cost more than $150 to fix or i want to treat myself to something shinny with racing stripes ... if times are, hard an excuse has to be a bloody good 1 (but i still wouldn't waste money on fixing it it it was going to cost me more than say $200 ... .I'd make do until i could afford a new system).
Next, I'll state the obvious - you get what you pay for. While i don't often recommend going for really top of the line equipment (where you pay for the gimmick factor) I'd always recommend going for mid-range or 1 up from mid-range. I don't build cheap & nasty systems - I simply don't want the comebacks; if 1 PC is $500 cheaper than the other .... where has the money been saved, do you really think it hacked off their profits? ... er no ! They've saved the money by spending less money, yes bulk buying will save a fair chunk, but not that much.

Next:- Laptop, Factory Built PC or Custom Build

Finally:- Software

OK, so what is Software? Software & hardware can be very easily distinguished by a very simple method. If you can literally put your finger on a part of the computer (dismantling it as necessary to get at it) then it 's hardware, if you cannot, then its software. While you can put your finger on your Microsoft Office install disk, you can't put your finger on Word or Excel (so the disk is hardware, the programs on it are software).