It seems you have posted this same question in several places as atoip and catpace. Note shotgun posting can lead to conflicting advice and confusing results.
It appears Cicero is now part of Median Computers, but I can find nothing of your model number at the US site. There are other Cicero models so I am guessing yours is not a US model - you have not posted your location to check their international sites. But it may just be too old.
That said, the advice you were given is sound. You should upgrade your XP SP1 to SP3. Remaining at SP1 puts you woefully exposed to security threats. You also need to determine more information about your computer, specifically the motherboard. Inspect the board for model numbers. Belarc Advisor
may provide some more information. As mentioned on another site, your 2002 system is too old to support PCIe. It might support AGP, and will support PCI. AGP will give you more options so look for an AGP slot. It will look similar to this
Here is my canned text on buying RAM. One of these might, if you are lucky, provide information on your system.
These popular RAM makers have auto-scanning and/or manual entry RAM wizards to help you determine which RAM is compatible with your motherboard. For manual entry, enter/select the PC or motherboard make and model number and the wizard will list compatible RAM.
Crucial - Memory AdvisorThe following retailers have auto-scanners and manual wizards. They sell brand name and/or "house" brand (re-branded) RAM.
Corsair - Memory Configurator (manual data entry only)
GeIL - Memory Configurator (manual data entry only)
Kingston - Memory Search (manual data entry only)
Mushkin - Advisor
OCZ - Memory Configurator (manual data entry only)
Patriot - Memory Search (manual data entry only)
PNY - Memory Configurator (manual data entry only)
SuperTalent - Memory Finder (manual data entry only)
Newegg - Memory Configurator System Tool
MemoryStock - Upgrade Configurator
18004Memory – Configurator
4AllMemory - Memory advisor (automatic and manual)
TigerDirect - Memory Configurator (manual data entry only)
Finally, before adding any hardware, you must
ensure your power supply can handle the additional load. My guess is you will need a new PSU too. Look on the PSU label for the specs.