How many memory slots do you have? If you've only got two, I'd start with a single 1 GB module if the computer can use that size. That way, you can later go to 2 GB. If you can't use 1 GB modules, I'd use 512 MB modules. 2 of them would be best.

I'm not sure what a wireless modem is. Can you tell us the manufacturer and model number? That may be what you need. Depending on your laptop, it may have wireless capability built in already. What brand and model is your laptop?

go get this free tool belarc advisor, install it and it will scan your pc then it will give you a wonderful list of every single thing on your pc and all the info about the pc, such as what type of memory you have and what type exactly your pc needs plus it will tell you how many slots you have and how many are open, it will also tell you the Maximum amount you can put on your pc which is of vital importance because it is not wise to purchase more than the pc can use. Then come back with all that info and we can tell you more.(you might want to print that out so you have it available)
By the way www.newegg.com is an excellent site for buying Ram for good prices I buy all of mine there,you can also buy many types of wireless routers there.
Belarc's
Depending on the type of RAm you have on your pc some types it is better to have 2 matching sticks like 2x512.

I did do a scan. I have two memory "ports" or whatever they are called. One already has 258 MB or whatever the exact memory number is 2 something. The other is empty. So if I get one 512 MB memory card, then they will not match and I will have approximately .75 GIG. With two 512 MB cards, I will have approximately 1 GB RAM.

I do not have a built in wireless modem on my computer, that's why my brother bought me one. But I have to have a signal. There are no free signals at my house, my friends already checked with their computer. That's why I want to get some kind of gizmo to "route" my cable connection to other spots in my house, in a wireless way. My friend already told me she has one in her house. I do not want to pay for wireless Internet access--it isn't cost effective for me at this time. I get a good deal for cable access through my phone company.

You can buy a wireless router almost anywhere that handles computer accessories. I have a basic $39 Netgear model. It might be a good idea to go with the same brand as the wireless modem (card?) that your brother bought for you. Setting up your wirless network is easy. Just follow the step by step instructions that come with your router.

I'm confused by your use of the term "modem" to refer to what your brother bought. Is this a wireless "card" to allow you to access a wireless network, or is it a wireless "modem" made to access cellular service? What you need, if I understand you correctly, is just a wireless "card" made by companies such as Netgear, Linksys, Belkin, etc.

As to adding more memory, be sure you get memory that is compatible with your computer and that falls within the limitations that your computer will take. Your comp manual should have this information.

you would want to have 2 512 cards or 2 1gig cards that is why I asked that you post what belarc said, what is the max amount it says your pc can take??? if it says 1 gig then you want 2x512 if it says 2gig then you want 2x1gig. And you definitely need to know the specifics of the type it tells you that your pc takes is it DDR? what number is associated with that? how many pin? you have to know exactly what you need.

get the info on what you are calling the wireless modem off of it and type it in here, brand, model number, what it says on it so we know what piece of hardware you actually have.

This is what he got me - from the box:
SMC Networks Wireless Cardbus Adapter
"Supports blazing wireless communcation at up to 108 MBPS."
Advanced Wireles Security, includes Wi-Fi Protected Access.
For Home and Small Office Networking.
"Share your existing cable connection with multiple computers by addind a high performance Barriade g Router with USB Print server"
Don't know about the last part, I could live without the print server, I just want to be able to work and browse in other rooms in the house besides my basement where the cable connection is.

As for the memory card - I went to the "Crucial" RAM Scanner Web site as recommended by Zep516 on a previous post that I found through the search menu. I clicked on the Crucial System Scanner, and it said:

Maximum Memory Capacity: 1024MB
Currently Installed Memory: 256MB
Available Memory Slots: 1
Number of Banks: 2
Dual Channel Support: No
CPU Manufacturer: GenuineIntel
CPU Family: Mobile Intel(R) Celeron(R) CPU 2.40GHz Model 2, Stepping 9
CPU Speed: 2392 MHz
Each memory slot can hold DDR PC2700,DDR PC3200 with a maximum of 512MB per slot.*

So I couldn't remember the exact number of what I have, but what I have is 256 MB of currently installed memory and one empty "slot."

yes and with that we know that the max you can have is 1 gig and you can only take that in the form of 2 sticks of 512MB each. So you would just take out the 256 you have and put in 2 new 512MB sticks.

here are some good options at newegg. I would have to guess it is 184 pin, that would be something good to know for sure.

CORSAIR ValueSelect 1GB (2 x 512MB) 184-Pin DDR SDRAM DDR 400 (PC 3200) Dual Channel Kit Desktop Memory Model VS1GBKIT400 - Retail

Kingston ValueRAM 1GB (2 x 512MB) 184-Pin DDR SDRAM DDR 400 (PC 3200) Dual Channel Kit System Memory Model KVR400X64C3AK2/1G - Retail
I usually buy Kingston brand and have good luck with it.

A-DATA 1GB (2 x 512MB) 184-Pin DDR SDRAM DDR 400 (PC 3200) Desktop Memory Model ADBGB1916K - Retail

IF this is a desktop (assuming it is) you want to make absolutely sure you do NOT buy anything labeled for laptops.
And lets get the terminology correct this is NOT memory cards a memory card is what you use in your camera, this is RAM memory sticks for the pc, or more precisely desktop RAM memory modules. If you ask for memory cards you will not be getting the right thing.

that should give you some idea of what to get. IF you run the belarc which will tell you exactly everything on your pc you might get the pin number too.

I think you said in your original email that you have a laptop. That's good since the wireless card you have is a cardbus adapter. It's a network interface card (NIC), not a modem.

The wireless card you got is one that will fit into the laptop. You'll now need a wireless router that will connect to the cable modem and then allow connections from other places within range. Depending on how much interference there is inside your house, you may be able to access it from anywhere in the house or you may find pockets that can't reach it. You may also be able to access it from outside your house (including from a neighbor's house) so you want to make sure you set it up with security. You should use WPA encryption and should also change the default password and SSID. There will be instructions on how to do that with the router.

The box says it will support speeds up to 108 Mbps. Your best chance at getting the highest speeds is to buy a router that is the same brand as the NIC (SMC). That may also make setting up the network easier (some manufacturers have wizards to simplify connecting to their own equipment).

I thought we were discussing 2 different machines one a desktop that needed more memory and one a laptop for the wireless set up. I guess I was wrong, no surprise there LOL.

So if it is a laptop the links to the RAM memory modules would NOT be the right ones, they are for a desktop pc.

But you can get the laptop versions for the same price range and newegg does have it I saw it when I searched for those.

Sorry I misunderstood and thought it was 2 machines. /Duh!

I only have the one computer, a Compaq laptop Presario 2100 model. Except I never put it on my lap because it is chained to the cable modem in the basement, (not literally).

It has two memory slots. One already has 256 MB memory, the other slot is empty.

I have a wireless card and I want to connect the cable modem I already have to a router to enable me to move the laptop around the house and "route" my Internet connection in a wireless way. It's the router I need to buy. The manufacturer recommends a "high performance Barricade g Router with USB Print server." This seems like too much for my intended use.

I am planning on doing a Windows reinstall to clean up the hard drive, and after I do that I want to install the additional memory and the wireless router.