After a good shopping at the computer market, probably you will be much exited to put everything into the box and fire up the bad boy. Assembling should never be taken carelessly, one loose screw, an improperly seated component can damage the system board, processor, chipset and Add-On Cards.
System Board
Make sure to read the manual that came with the motherboard - instructions may differ for every board. If the motherboard isn't correctly installed you will face problems like overheating and system crashes (computer "freezing", "locking", "resetting" etc).
The first step is to open the case and locate the metallic plate where the motherboard is screwed in. Normally this plate can be removed from the case by unscrewing it from the back end of the case and sliding it. You must remove it from the case to install the motherboard on it. You should lay down the motherboard on the metallic plate and check which holes from the metallic plate match the holes on the motherboard. On the holes on the metallic plate that matched a hole on the motherboard, you will install a nut screw or a rivet nut. On the holes that don't match a hole on the motherboard, you will simply leave it away. Sometimes you will find some holes on the motherboard that don't match any hole on the plate.
Make sure board is not touching metal anywhere other than the rivet or nut screw heads, the board circuit may shot as soon as power flows.
Few links for better understanding:
http://www.hardwaresecrets.com/article/145
http://www.pchardware.co.uk/install-motherboard.php
http://www.build-your-own-computers.com/how-to-install-a-motherboard.html
Processor
Great precaution must be taken while Installing/Removing/Cleaning Processor and Installing/Removing Heatsink. There are two types of processors: Pin Grid Array (PGA) Package & Land Grid Array (LGA) Package Most of the processors available today are LGA Package.
AMD Processor Installation Videos is a great resource for Installing/Removing/Cleaning Processor and Heatsink.
Memory (RAM)
Make sure to discharge any possible static buildup before touching RAM; it is extremely sensitive to ESD (Electro-Static Discharge). Do this by touching something metal before touching your computer. Do not touch the metal parts on the RAM chip. Every time you touch the gold portion of it, you are running high risk of ruining 64MB of RAM. You should be well informed about the Number of RAM slot on the board, Speed of existing RAM modules (If Any) and Maximum amount of supported RAM on the Board.
Links for video tutorial:
http://www.wikihow.com/Install-RAM
http://www.ehow.com/how_895_install-ram.html
http://www.build-your-own-computer-tips.com/install-ram.html
Power Unit (SMPS)
Installing Power supply is fairly simple and neat.
Just a word of caution, make sure to set the Voltage on the back of the Power Unit according to your country standards else, you may experience unexpected outcomes.
Links for video tutorial:
http://video.about.com/pcsupport/powersupply.htm
Storage (HDD)
Hard drive installation is easy; however, jumper settings can make it tough. Jumpers on the hard drives decide on how the HDD will be represented to the BIOS. I mean, Jumpers settings decide which HDD will be given priority for Boot. Wrong settings won’t let BIOS see the Hard Drive.
Precaution: While installing Ultra ATA data cable with Blue board connector (Ribbon), mind the grove on the connector on the board and hard drive. Preferably, check the placements of pins on the board/HDD and the connector lest you break the pins on the board or hard drive. Be aware of the Master and Secondary points on the connector.
Setting the Jumpers
Cable Select. The drive is configured at the factory for a cable select setting. This allows the drive to assume the proper role of master or slave based on the connector used on the cable. For the cable select setting to work properly, the cables you are using must support the cable select feature. Current UltraATA cables with the 3 colored connectors do support this feature.
Master or single drive. If you are installing your Seagate hard drive as the only drive in the system or if it will be the primary boot drive for the system, the jumper should be set on pins 7 and 8.
Drive as slave. If you are installing the drive as an additional drive in your system, the drive should be set as slave by removing all jumpers. Remember to confirm that the original drive is set to a master position (If the limit capacity jumper is required for your installation it will need to remain in place).
Drive as master with a non-ATA-compatible slave (Seagate drives only). Set a jumper on pins 5 and 6 and a jumper on pins 7 and 8. Use this jumper setting only if the drive does not work as a master.
Limit drive capacity/Capacity Limitation Jumper (CLJ). Use this when either you start up your computer and see the message, "Hard disc drive controller failure", your computer does not recognize your newly installed hard drive, or your system stops responding during the boot process after installing this new drive. If this jumper is required, your system cannot support a drive this large and can be updated with a PCI controller card.
Refer Seagate Jumper Setting for in-depth understanding (Link applies for ATA Hard Drives, SATA hard Drives & SCSI Hard Drives):
http://www.seagate.com/www/en-us/support/installation_assistance/jumper_setting_illustrations/
Mishaps that may happen if not careful• Power supply if not firmly screwed into the cabinet, may fall on the Add-On Cards (Graphics, Sound, TV Tuner and other PCI/PCI(e) cards).
• If the any of the video card's heatsinks are secured with fragtape(High Performance Thermal Tape), they will promptly fall off and land on the modem/NIC/sound card below.
• If the cabinet is not big enough, it if possible that the Power Unit cables or other cables can land on the processor fan and hinder it from running. You may not even know this happened because all you did was clean the cabinet exterior or moved the box. If this gets serious issue then you will hear increased fan rotation from the box. Because CPU is reaching high temperatures so, BIOS will trigger increase fan rotation. Finally, it may reach a point where system will crash and processor dead. Whenever you hear increased fan rotation reboot the machine into BIOS and check the system temperature and all fan status.
I hope this article was helpful. Please let me know your comments and suggestions. Appreciate your time.