Is a Computer with a Smaller Ram Capacity is Likely to Get Slower with Time Than a Pc with a Larger Ram?

I have a laptop since almost 5 years, and its RAM capacity is only 240MB. My sister's laptop is 2 years old and its RAM capacity is 512 MB. This laptop is slow and it usually says virtual memory is low. My first question is Do i have to change the RAM of this laptop to work faster? And the laptop with the larger RAM is less likely to slow down with the same age? I really need to know so that I buy a RAM if needed.
Thank you

Suggestion:

yes you need more ram.

before you get any ram, you need to find out if you actually have the slot to expand your ram.

Windows will get slower over time, i normally reinstall my windows every 2years to give it a fresh life.