I think I am correct about your machine being low on memory.
Here's your situation.
Your computer appears to be an IBM ThinkPad A20m with a 700 MHz Pentium III processor and 2 RAM expansion slots capable of supporting 512 MB of RAM.
The good news is your machine will support 512 MB of RAM and a 700 MHz PIII machine has reasonable performance, not a rocket ship with Windows XP and Anti-Virus, but should work ok with enough RAM. I have a 500 MHz PIII that I run Windows 2000 with reasonable success.
The issue here is you will need to abandon both of the current 128 MB RAM modules and upgrade to 512 MB of RAM using 2 - 256 MB RAM modules. If you buy from MemoryX it looks like about $160. Not a cheap proposition, but cheaper than a new laptop. This appears to be a good price on RAM, only other way is to buy used on e-bay, but there may be some risks. You may be able to sell the 128 MB RAM modules to regain some of your capital investment? Again, ebay is a good place to sell used RAM.
To increase your machines RAM:
You will need 2 of these module - 256MB IBM Thinkpad 144p PC100 SDRAM SODIMM (p/n 33L3069) $79.98
RAM is not hard to install, you just need to use care when handling and installing it. The hardest part is finding where it is installed getting access to it. It appears that the RAM is located on the underside of the laptop. IBM's support site has this useful link about your machine:
http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-46015
As for your process using the CPU, it appears to legitimate. Do not know if it is supposed to behave in that manner. Maybe additional RAM will cause this process to settle down.
mcshield - mcshield.exe - Process Information
Process File: mcshield or mcshield.exe
Process Name: McAfee VirusScan
Description:
mcshield.exe this process is associated with McAfee's Internet Security suite. More specifically, it is essential to the Antivirus software and should not be removed.
Author: Network Associates, Inc
Part Of: McAfee's Internet Security suite
Good luck!
JamesO