Stand offs are used between your case and motherboard. Some cases have them built in, some you have to screw in yourself. The purpose of them is 2 fold:
1. To provide space between your motherboard and the case. It prevents componets from shorting to the chasis ground.
2. Provides a ground between motherboard and case chasis.
If you don't use them, you typically here a pop, then see or smell the blue smoke when you apply power. It typically kills the motherboard. As I stated and someone else as well, occaionally you get lucky and the board will still work.
Nothing went wrong but I was a lil scared when I flashed my BIOS on my brand new 486 DX-4 100. I had been using for years before that, but its always a lot more scary when you worked F0REVAR to get the cash to buy the parts all by yourself...
First build went pretty good. Intel 486DX@33MHz, 4MB of ram, 260MB HDD, 2X CD-ROM, Acer Sound Card, 256k VGA Card. I had to gut an old proprietary 386 and built it with all used parts I had and some I picked up at a local computer recycler...that was 1995 I believe. I have built my own ever since
I also made the mistake of not using all the stand-offs...it was kinda shorting out, but I got it figured out.
The only part I bought that wasn't compatible was a 120mm fan when my case only has sopts for 80mm. Don't ask me how I overlooked that one...
I didn't have too many real problems, although I nearly went insane trying to figure out why Windows wouldn't see my SATA drives. (Drivers, drivers, DRIVERS!)
The only thing I definitely do differently is look for better values. I've found out that I could've gotten a better PC for the same price I paid. But I don't think I did too bad, considering I had just started to get more interested in computers.
Somehow I got a shipment with a loose CMOS battery that would only sometimes make contact, so it would POST only so often. Took me forever to remove everything and figure that one out.
Other things I've had go wrong:
Ordered the wrong Heatsink (Pentium version vs. A64)
Overclocked and blew out my modem
CMOS setting reset to default (new mobo needed a new battery, such crap)
Stabbed a screwdriver through a mobo I was trying to revive by attaching a stock AMD heatsink to. Somehow it still posted and runs fine(I didn't need any of the parts, so I was willing to risk frying them).
Problems only arise when you act retarted. For instance, a kid was semi-building a custom rig down my street. Me and my other computer-competent buddy were putting it together for him. Naturally it didn't come with a HSF so he had to buy one.
Once we left he thought "I doubt it can hurt to run this thing for only a few minutes without a heatsink on".
I'm sure you all can imagine how it went from there
I was lucky enough to have everything go perfectly on my first build. It was a:
450mhz K6-III
Gigabyte mobo
13.6GB Quantum Fireball CR (Still working in testbed rig!)
128MB generic PC-100 RAM
16MB TNT video card
Sound Blaster Live! value
6x DVD Rom with mpeg-2 decoder card
Superdisk drive
19" CTX monitor
Full tower ATX Aopen case w/ Aopen 350W PSU
Microsoft Natural Elite keyboard - Still being used on my main rig!
Logitech mouse with scroll wheel.
Stupidly bought the wrong type of RAM..didn't take long to correct though. Also had a small problem installing the OS, but that was also worked out quickly. *Is thankful*
I had problems with the BIOS and the harddrive boot order because I was trying to use the Abit "Seriellel" (whatever it was called) adapter with the SATA interface. Other than that, everything went together smoothly.
My first build was actually kind of a rebuild. I got a new motherboard and video card, and took the rest of the parts from an HP Pavillion, and put it all in a new case.
(I really just wanted a video card, but knowing HP and their proprietary parts/BIOS/OS, it probably wouldn't have worked without a new motherboard. A new motherboard meant a new copy of Windows, since the HP didn't actually come with a CD, just a stupid "recovery partition." I got a cheap copy of XP Pro through my university.)
For some reason, no matter what, every time since then, I always seem to get the RAM backwards. It's not a huge issue, since the DIMMS are keyed, but I struggle for several minutes wondering why it won't go in until I realize it. It happens without fail.
I also usually run into some issue where I forget to wire a header, plug in a cable, or flip a switch. (In addition to unplugging, I usually switch off the PSU when I'm working inside the box or transporting it. You wouldn't believe how many moments of panic that caused.
*Push* "OMGWTFOMGWTF --- Oh..." *Flip* *Push* "There it goes."
I also managed to break a CD-ROM during this build. I think it broke pulling it out of the HP case. The faceplate got caught on the case and I yanked on it, and I think I pulled the tray out of alignment. Windows still recognized it, I just couldn't open it. The faceplate for the floppy drive was also built into the front bezel, so when I moved the drive to the new case, it was (and still is) ugly as hell. I really don't need the drive, but having it gives me a nice feeling of security.