Could help...

On my setup, the task manager (CTRL+ALT+DEL -> Performance) shows:

Totals:
- Handles: ~5552
- Threads: 297
- Processes: 29 (20 norm, "clean install")

Physical Memory (K):
- Total: 1048048 (2x512 RAM)
- Available: ~739672
- System Cache: ~178052

Commit Charge (K):
- Total: ~188896
- Limit: 2521088 (-RAM=assigned swap area) In my case a waste of HD space.
- Peak: 432000 (At start up)

Kernel Memory (K): (Little fuzzy on what this is, exactly.)
- Total: ~63276
- Paged: ~32944
- Nonpaged: 30336

WinXP Pro (SP2)/~2.1Ghz

Haven't actually clocked it yet, but it boots fast 

Quoting JonM:

Quote:
Is this a laptop then that we are discussing?

He said he had Vaio, so that would be a Sony laptop.

Quoting Ron:

Quote:
As a lot of others have said,  XP with only 128 Meg Memory, will good ok (we have a lot of customer's running P1 & P2 with only 128 on XP)

But, if your mother board will allow it, I do recommend upgrading to 256 or higher.
XP really starts to "feel" good at 512 and above. 

FYI,  my two XP machines are running 1G and 2G memery. While my Vista machines are running 2 G and 4Gig.

Over the years, I've noticed that while Windows may run (and I emphasize 'may') in the minimum amount of memory, it puts a hell of strain on the whole system that can cause things to break prematurely.  Windows uses a swap file, and if there isn't enough RAM it will use virtual memory.  The more VM it has to use, the slower it works, and the harder the hard drive has to work to take care of the I/O involved.  When hard drives were smaller (measured in megs instead of gigs) that led to a lot of HDs dying early.  It also puts a strain on the CPU, video card, cooling system, etc.

So, I made it a practice with all my customers/clients to recommend a minimum of at least twice the RAM MS said was minimum, and if they could afford it, 3 or more times.  A lot of them thought I was some kind of magician because of how much better it ran.

Hardware is better today than it was then, but the same things apply.  Increase the load and you stress the parts more than necessary.  Sort of like putting a lawnmower engine in a big Caddy.  It may move you down the road but it won't last as long as the regular engine will.

Somebody said this was a notebook, and if it is, what I said goes double.  All those parts are even smaller and more susceptible to overstressing.  I would advise my clients in such cases to max out memory, because most notebooks don't run as much RAM as desktop PCs are capable of.

XP with 128??  will a Model T tow 80,000 pounds?.....

Quoting scottiew:

Quote:
it is not a laptop. it is a normal desktop Sony Vaio pc.

OK.  Wasn't aware they made a desktop Vaio.  Have only seen the notebook types.

To answer the question on whether you can run the system on 128 MB of RAM: Probably.  I once got a system using Win2K up and running on 64 MB of RAM with about 15 MB free for running programs at startup.  I'm pretty sure I could get XP running in 128MB.  However, to do so you need to be able to heavily optimize what all gets run on the system, and if you're not comfortable with RAM upgrades you certainly won't be able to work through those custom optimizations.  Messing with that stuff when you don't know what you're doing can seriously screw up your system.

For considering the RAM upgrade, I'd recommend going to http://www.crucial.com. Use their Memory Advisor Tool to figure out which type of RAM you need and how much your system can actually hold, plus a general idea on the cost (Crucial is a little bit on the expensive side, relatively speaking, but they provide quality products and have good customer service; also, you don't have to buy from them if you can find the same chips somewhere else cheaper, such as wherever you get the OS from).  For example, if you had a Sony VAIO PCV-E204, you can have up to two 128MB sticks for about $37 each.  There's also a Scan Your System thingy which may be easier for you to use as that will also tell you what type of RAM you already have and how many slots you have filled/free.  Get as much as you can afford (after the cost of the OS), and will fit in your system.

Before doing the install (and I'll echo that you really want to do a clean install), back up everything you can. Start going through every directory you have and backing it all up: music, pictures, program downloads, documents from the My Documents folder or elsewhere, bookmarks from the browser, etc.  This is a long and tedious process.  Go through everything at least twice, because you're sure to miss something the first time through.  It's much easier if you have a second hard drive you can just copy everything too, or a second partition on the hard drive you have.  Otherwise, start making CDs.

And as for actually installing the new RAM, if you don't want to touch it yourself, just find a friend who's at all comfortable with computers.  Installing RAM is pretty easy.  If nothing else, take the computer and the RAM chips down to a local computer shop and have them put it in.  It should be a trivial cost, if they even charge you at all.