Computers run slow for many reasons,heat being one of them.check fans,dust,etc.
Click HERE for instrutions on How To Shut Down Unnecessary Start Up Programs
Click HERE for instrutions on How To Clean Unwanted Files From The Hard Drive.
Also scan for spyware,viruses,and so on
You might want to install CCLEANER
Your memory issue could be a virtual memory issue,click HERE
Dell Inspiron 600m-XP home edition 2002,SP2,1.4GHzProcessor 256MBRAM. This is our computer which now suffers from very slow performance. Many times the computer don't respond at all. When I manually turned off and on again there are messages generated that say --- decreasing memory in your system,press F1 to continue,F2 to reset....