Anyway, these are the specs that I found at hp.
For proper system operation, if your system supports DDR-SDRAM DIMMs, the DIMMs must be industry-standard 184-pin, unbuffered PC1600 200 Mhz or PC2100 266 Mhz-compliant, 2.5 volt DDR-SDRAM DIMMs. The DDR-SDRAM DIMMs must support CAS latency 2 or 2.5 (CL = 2 or CL = 2.5). They must also contain the mandatory JEDEC SPD information. DIMMs constructed with x4 SDRAM are not supported; the system will not start using unsupported DIMMs.
After checking with dmidecode, my system is currently running 512mb at 266mhz, however, I don't know what kinds of DIMMs the chips are, but will turn it off and have a look at them after I'm done writing this.
So, is there a simple way to discern what kinds of memory I can use or not and simple terminology to use in google, or better yet a place to find this exact type of memory cheap, if possible?
This one seems like it would work, but the CAS latency is 3. Also, it states "128x4 X 2 DDR SDRAM CHIP CONFIGURATION", I don't know if that's the x4 SDRAM that are not supported in my computers specs. I do know that the speed is not important as long as it's not less than 200mhz.