Upgrading old computer - Which memory to choose?

I have an old Computer that's running Window XP at the moment.

here is the spec:

OS Version: Microsoft Windows XP Home Edition, Service Pack 3, 32 bit
Processor: Intel(R) Pentium(R) 4 CPU 2.80GHz, x86 Family 15 Model 2 Stepping 9
Processor Count: 2
RAM: 511 Mb
Graphics Card: RADEON 9200 SERIES, 128 Mb
Hard Drives: C: Total - 152617 MB, Free - 91723 MB; I: Total - 476937 MB, Free - 403223 MB; R: Total - 15 MB, Free - 15 MB;
Motherboard: , P4X400-8235
Antivirus: Microsoft Security Essentials, Updated: Yes, On-Demand Scanner: Enabled

One of the main things to do is to put in some more RAM, but...

According to Speccy I have:

RAM
Memory slots
Total memory slots 3
Used memory slots 1
Free memory slots 2
Memory
Type DDR
Size 512 MBytes
DRAM Frequency 133.2 MHz
CAS# Latency (CL) 2.5 clocks
RAS# to CAS# Delay (tRCD) 3 clocks
RAS# Precharge (tRP) 3 clocks
Cycle Time (tRAS) 6 clocks
Physical Memory
Memory Usage 77 %
Total Physical 511 MB
Available Physical 112 MB
Total Virtual 1.22 GB
Available Virtual 611 MB
SPD
Number Of SPD Modules 1
Slot #1

Which doesn't tell me much...

So I understand that I have 3 memory slots and I using 1
But what kind of memory should I buy, there must be gazillions of different versions...

// Anders

Supports up to 3.0GB DDR200/266/333 SDRAM which you can find real cheap now, heck, I might even have a few sticks around here by me.

Thanks for the info!

Just so that I get it right (hardware is NOT my thing...)

It looks like I can get some Crucial or Corsair from my local dealer. Could you please suggest which "version" to buy?

// Anders

I feel a bit silly, but....

I can't find the exact models that you pointed at, but what about this:

Corsair Value S. PC3200 DDR-DIMM 1GB VS1GB400C3

Would this be a suitable memory?

// Anders

Go to Crucial.com.

When there, you can let it sniff your PC and it will tell you what Crucial RAM is known to be compatible.

Or enter your PC make and model number into the configurator and it will show you the compatible RAM.

http://www.crucial.com/uk/store/dram...800:s&mpch=ads

That was easy!

OK, now I have ordered 3 x 1GB of memory.
Hopefully I will be able to insert them into my computer
As I said Hardware isn't my cup of tea!

Thank you all for the help!

// Anders

Make sure your computer is switched off with the power cord disconnected.

Use an anti-static lead if you have one and be careful to hold the RAM modules by the edges.

Make sure you insert them the right way round and don't try and force them.

If you check Crucial's site I do believe it has a video showing you how to fit RAM modules.

Please keep us posted about the outcome. :)

Fyi:
DDR-266 = pc2100
DDR-333 = pc2700
DDR-400 = pc3200