Hi FullFool,
The browser does begin to slow down after remaining idle for awhile or opening more than two tabs, but I'll assume that's normal.
That "may" be normal for your machine, but I'd say probably not.
Windows XP does a pretty good job of releasing resources, and shouldn't accumulate slowness with time.
You will probably be favorably rewarded when you make the adjustments as recommended in your Pit Test.
Give us a shout after you've finished up with Rip Chain, and made followed the Pit Test recommendation.
We'll have another look if you post a fresh Pit Test TechExpress at that time.
Then we may be able to provide some additional recommendations to further enhance performance.
By way of comparison:
Here's my machine, with is an older low resource machine, and truly lame as compared to yours.
http://www.pcpitstop.com/techexpress.asp?id=FAPJHW4NGFVSTG8V
But right now as I'm typing, I have 12 instances of Firefox open, some with multiple tabs too.
I have 5 documents in Winword open , two Notepads, and one Foxit PDF,
Yahoo IM is open and in action, and two instances of Windows Explorer.
Now that may seem like an absurd amount of open windows, but I'm presently working at several Forums, preparing documents here for work locally, and keeping in touch with my family.
The machine is handling it fine.
What makes the difference?
Well, aside from my Pit Test recommending to Defrag, I've pared down the startups, and have more % of Free Space.
Having an AGP video card takes the borrowed load off my RAM so that I have the full 512, that you could have too, by just picking up an old AGP for $20 or $30.
You will probably improve your Internet download by correcting your TCP Receive Window Size. Download should be much faster than your upload.
Otherwise there are some System Configuration settings that you may want to consider for performance.
I hope I don't sound like I'm bragging. This is really a lame old machine with nothing much to shout about.
But it serves well.
Yours can probably pick up the pace quite nicely with a few adjustments.
I hope you check back in when you finish up at Malware Removal.
Best Regards