Let's take one thing at a time.
First, it is never a good idea to install an operating system update (for instance SP3) until the machine if running well and free of other problems. (Good job – You have already ruled-out malware infection, which should always be considered BEFORE installing software of OS UPdate)
While there is no reason that I have found to avoid SP3 with a Toshiba machine (the way it was a problem for HP machines until HP and MS issued a patch), I would still hold off on installing SP3 until you have completed the other recommendations of the PCPitstop Full Tests recommended Fixes AND the suggestions I've posted below. (I'll have a few more for you after these are completed)
Second, it appears that "some" of your problem "could" be related to chipset and device drivers.
I'd recommend that you go to the Toshiba website, find your machine, and download and install a fresh set of Chipset and device drivers.
(let us know what difference that may make, if any)
Third, and maybe this should be first…. Your Hard Drive is 26% Fragmented. That is a huge amount of fragmentation.
Reboot into Safe Mode and Run your Accessories - System Tools - Disk Defragmenter
Run it TWICE.
(let us know what difference that may make, if any)
Fourth, you are correct that 512mb RAM is a relatively low amount, but adequate for XP. However, from that 512mb the video adapter may be "borrowing" some of the RAM, leaving you less available for OS and applications.
If you have the budget for it, XP will run more briskly at 1gb (2x512mb) and "may" run even better at 2gb (2x1gb) (I personally prefer 2 gb)
__________________
You have a "TON" of processes Running Active in the background, most of which can be turned off via MSCONFIG.
"I'll separate the list into
"Should turn off - unless using" - Recommended
"OK to turn off - unless using" - Owner option
These processes are "consuming" 8% of your CPU and 312mb of your Physical RAM, just in the "Resting State" before you activate any applications or try to run anything or even try to browse the internet.
Total 65 - active processes running.
CPU Utilization 8%
Total RAM Used MB 312
RAM Utilization 62%
"Should turn off - unless using" - Recommended
Intel Hotkeys Intel® Common User Interface Intel Corporation 0 0
Realplayer - Schedule RealPlayer (32-bit) RealNetworks, Inc. 0 0
QuickTime Icon QuickTime Apple Computer, Inc. 0 0
HP software update hp digital imaging - hp all-in-one series Hewlett-Packard Co. 0 0
HP Digital Imaging hp digital imaging - hp all-in-one series Hewlett-Packard Co. 0 2
Intel® Common User Interface Intel® Common User Interface Intel Corporation 0 0
User Interface Intel® Common User Interface Intel Corporation 0 0
HostManager AOL Service Libraries AOL LLC 0 3
ViewpointService Viewpoint Manager Viewpoint Corporation 0 0
"Suggest" you fully Uninstall anything Viewpoint via Control Panel - Add/Remove
Realtek HD Audio Realtek HD Audio Sound Effect Manager Realtek Semiconductor Corp. 0 2
"OK to turn off - unless using" - Owner option
Aim AOL Service Libraries AOL LLC 0 1
TOSHIBA Power Saver TOSHIBA Power Saver TOSHIBA Corporation 0 1
Legitimate WinLogon Microsoft® Windows® Operating System Microsoft Corporation 0 1
Logitech QuickCam Logitech QuickCam Logitech Inc. 0 1
HP digital imaging hp digital imaging - hp all-in-one series Hewlett-Packard Co. 0 1
Toshiba Software Update File not found File not found 0 0
TOSHIBA Applet TOSHIBA TAPPSRV TOSHIBA Corp. 0 0
Logitech QuickCam Logitech QuickCam Logitech Inc. 0 2
ConfigFree ConfigFree™ TOSHIBA CORPORATION 0 0
Google Update Service Google Updater Google 0 0
Logitech QuickCam Logitech QuickCam Logitech Inc. 0 0
Logitech QuickCam Logitech QuickCam Logitech Inc. 0 0
Digital Camera Control Logitech QuickCam Logitech Inc. 0 1
StrgSync.exe File not found File not found 0 2
Acoustic Drive Silencer CD/DVD Drive Acoustic Silencer TOSHIBA 0 0
TOSHIBA Power Saver TOSHIBA Power Saver TOSHIBA Corporation 0 0
TOSHIBA Zooming Utility TOSHIBA Zooming Utility TOSHIBA Corporation 0 0
Toshiba Hotkey THotkey TOSHIBA 0 1
Speech Microsoft® Windows® Operating System Microsoft Corporation 0 1
<– this is a special case, see below
Outlook email Microsoft Office Outlook Microsoft Corporation 0 41
Intel driver Mobile Unit Support Service Intel Corporation 0 0
8021XConfig Module 8021XConfig Module Intel 0 1
Event Engine EvtEng Module Intel Corporation 0 0
Communications Helper Logitech Logitech Inc. 0 1
TOSHIBA Virtual Sound TOSHIBA Virtual Sound TOSHIBA Corporation 0 0
Toshiba Pinger Software Upgrades TOSHIBA Corporation 0 1
ConfigFree Tray ConfigFree™ Tray TOSHIBA CORPORATION 0 1
Turn off "Speech - cftmon.exe"
Open Control Panel
Double-click on Regional and Language
Select - Language(tab)
Press - Details(button)
Select - Advanced(tab)
Place a checkmark/tick in front of "Turn off advanced text services.
Follow the other recommended fix suggestions from the PCPitstop Full Tests.
*** Don't get distracted into buying their automated fee based tools. ***
There is nothing in the PCPitstop Results that cannot be fixed manually, and we will help as necessary.
Let us know how you are progressing.
Best Regards,
Doug