How do i make my pc run as fast as its specification?

this is a 1year old..fujitsu siemens computer..it has 27.6GB FREE out of a 149GB Capacity

Intel Pentium 4..3.20 GHz..

2.78GHz, 512 RAM

I haved got around 30GB of movies, music and pictures saved, 50GB of games installed and game files and rest are the programs

the problem is:

Booting the pc and waitin for logging into any specific account is a big headache..in short..the start up takes too long

when i shut down..its the same problem and on top of zat i always get promts like that:

'The application failed to initialize bcoz the windows is shutting down'

there are some programs which don't respond quickly

When I click on an icon..it takes long to open..somtimes..very very long..15-20 minutes!

i usually work with a maximum of 4-5 programs at d same time..e.g: AOL, Internet Explorer, Yahoo Messenger,MSN Messenger, Azureus,games like Nedd4Speed Carbon or Fifa 07

I have got a pretty useless antivirus..EZ Armor!

what should i do??

Increase free space on?How to do Registry clean?

How do i make my pc run as fast as its specification?computer

Use registry cleaner can make your pc faster,the reason is that there are some regsitry errors in your PC to cause "Computer slow".

Every time you install and uninstall software on your computer and surfing online you create junk in the registry.You need to scan and clean your PC with registry cleaner to make your pc fater.Good Regisry Cleaner will improve your PC and Internet performance dramatically.It even can speed up your PC by 300% or more!