Windows 7 - What are the reasons of an old PC slowing down?????

Hello, Good Morning
I have a Sony VAIO VGN-AR190G, it is 2006 edition, had Windows XP Media Edition 2005
It has Intel Centrino Duo processor running at 2.00GHz, 3GB of RAM, 200GB HDD, 17"XBRITE HiColor display of 520MB, Windows 7 Ultimate SP1, and system rating is 4.3
It has been a little slow, since it is somehow old, and it may be tired
I want to know what slows down an old pc,
If it is the processor, is it OK to disassemble it and change the processor with a Core i3 one??
I am afraid of doing it, it may damage the motherboard...
Please anyone help me, thanks in advance...

Hello beyar and welcome to Seven Forums.

I'd start with the suggestions in this Microsoft article.

How to make your computer run faster: 6 tips to increase PC speed

Then you could look at some of the Windows 7 Optimization suggestions here:

Optimize Windows 7

Before you start tweaking things I'd suggest you make a system restore point. Better yet, a full system image to an external hard drive.

System Restore Point - Create

Installing an OS that is more demanding on resources

7 is quite a bit more demanding than XP MCE.

"Good news" - you don't have to be afraid because it can't be done. The i3 range is a completely different socket and thus, impossible to replace.

Realistically, the only thing worthwhile replacing to give a performance boost would be a new 7200rpm HDD or better yet, a SSD.

I just finished installing Windows 7 on a Pentium 4 system (200GB 5400rpm IDE drive, 3GB RAM, Radeon 9800 Pro) and was please with how well it runs Windows 7. No noticeable performance issues.

Some things that can cause slow-ness:

• Having too many programs starting when the computer starts is always a big one.
• Having too many processes running at once.
• Using Windows 7 Aero desktop with a graphics card that can't handle it.
• Having a hard drive that is near full (over 75%).
• A hard drive that is badly fragmented.
• A device driver that is not fully compatible.
• Some modern Antivirus programs are very demanding of system resources - you could try changing it.
• Many current versions of browsers use more system resources then they used to.
• Many modern programs use more system resources then they used to.

Open the Task Manager and go to the Performance Tab and look to see if the processor and memory is running high at idle, and then check it while running programs or when you think the PC is running slowly.

Check your Event Viewer and look at the list of "Critical" and "Error" listings for clues to any problems that could be directly responsible.