I have Dell Dimension 3100 Desktop PC but I miss COM ports (serial and parallel) driver

Means that that device is defective or missing software drivers.

There does not seem to be a valid Windows 7 network driver:
http://ftp.dell.com/Pages/Drivers/dimension-3100.html#Network

You can try the driver for XP to see if that will work, otherwise you may need to buy a new NIC card.

Have you upgraded your OS to Win 7? If so this is a common problem, use the Vista driver found here: http://www.dell.com/support/drivers/us/en/04/Product/dimension-3100 Have you done ALL the Windows updates? Take a look at changing the Compatibility of the driver . Download the driver and Save the file to a folder, Use this procedure to change Compatibility : http://www.howtogeek.com/howto/windows-vista/using-windows-vista-compatibility-mode/ For further assistance respond to this post.

Go to:
http://support.dell.com/support/downloads/driverslist.aspx?c=us&cs=19&l=en&s=dhs&ServiceTag=&SystemID=DIM_PNT_P4_3100&os=WW1&osl=en&catid=&impid=
Once there, select your operating system from the drop-down. Then select the Audio driver in the section below.
Let me know if this is helpful for you.

U can download from this link http://drivers.softpedia.com/get/NETWORK-CARD/OTHER-NETWORK-CARDS/Dell-Dimension-3100-Intel-LAN-Driver.shtml

You can found the drivers on Dell Support site for Dimension 3100 Desktop PC thru here.

If you had reinstalled your OS you may have to download Chipset first then second Software Utilities and lastly Video drivers.

The drive you are installing is a SATA drive. The system came with a PARALLEL ATA or PATA optical drive, The motherboard has a SATA controller and the HDD is a SATA drive. So you need a SATA data cable and connect it to the SATA 1 port on the motherboard. There should be a SATA power connection inside the chassis that is not being used, that you can connect to the drive. Then go to system setup (F2 at boot) enable the SATA 1 controller and disable the PATA controller
http://support.dell.com/support/edocs/systems/dim3100/en/sm/parts0.htm#wp1043338

No, it does not.
Check the specs of your desktop PC here:

Ports and Connectors
Externally accessible:
Serial
9-pin connector; 16550C-compatible
Parallel
25-hole connector (bidirectional)
Video
15-hole connector
Keyboard
6-pin mini-DIN connector
Mouse
6-pin mini-DIN connector
USB
two front-panel and four back-panel USB 2.0–compliant connectors
Network
RJ-45 connector
Audio
three back miniature connectors for line-in, line-out, and microphone
Headphone
one front miniature connector for line-out

Ports and Connectors
Externally accessible:
Serial
9-pin connector; 16550C-compatible
Parallel
25-hole connector (bidirectional)
Video
15-hole connector
Keyboard
6-pin mini-DIN connector
Mouse
6-pin mini-DIN connector
USB
two front-panel and four back-panel USB 2.0–compliant connectors
Network
RJ-45 connector
Audio
three back miniature connectors for line-in, line-out, and microphone
Headphone
one front miniature connector for line-out
http://support.dell.com/support/edocs/systems/dim2350/specs.htm#1107078

click on start,goto controlpanel,you will see a speaker diagram click on it to increase the volum.but if it is blunt you have to contact your IT person to install the driver you need

www.thesimsresource.com/downloads/free/sims2/
www.parsimonious.org/
www.aroundthesims2.com/

Try these sites