I'm going to assume a few things, 1- you don't mind spending a few dollars to upgrade, 2- you have the ability
to repair your own system, 3- you understand I'm suggesting you investigate your options and issues before
you actually make any changes, 4- ALREADY mentioned -> BACKUP any important data first.
...Your processor is descent and would function nice with 2 GB of RAM, assuming your motherboard is in good
shape and worth the investment. I'm not positive but I believe you have the socket 478 Northwood, 2GB of
RAM is about $35 (U.S. / Newegg) more than a single stick of 512MB - you don't mention your system specs so
I'm guessing the RAM you need. I stepped up from an Athlon XP 1.5Ghz/1GB RAM to 2.1Ghz/2GB RAM - WOW!
...What shape is your hard drive in? Is it old and tired, 5400 rpm / 7200 rpm? How much free space is available?
This info along with whether or not you use "restore points" or "Indexing" can have a serious impact on your
system speed. You would be amazed at what a new drive could do, or simply free up some space on the one
you have. If it is SMART capable I would check the Power-On hours (Uptime), as well all Critical details.
...Have you updated your motherboard chipset drivers recently, what about other important drivers?
...Don't forget to have a look at BV's Services suggestions - they work, if for no other reason than why have
more services / processes running than you have need for?
...Don't forget to scan for malware, viruses etc - they can impact a system as well.
You say little about what you use your computer for so no one can really offer much in the way of specifics but
what has been mentioned is a start. You definitely need more RAM, maybe some housecleaning of old programs,
update some drivers and disable a few unnecessary services - all this is a good start in the right direction.