<<...have recently installed new memory chips...??
Unimportant if you were infected at the time of installation. New hardware has no impact on infected systems.
<<...I'm also suspecting it having multiple infections...>>
If that's true, then you probably need to post at BleepingComputer.com - Am I infected What do I do - http://www.bleepingcomputer.com/forums/f/103/am-i-infected-what-do-i-do/
, rather than here in XP forum. This forum is designed to treat Windows issues, but malware issues are not Windows issues and require guidance that is beyond the normal scope of persons trying to assist users...in this forum.
Strange statement...being disconnected from the Internet doesn't eliminate the chance of infection, but it certainly reduces it. If the disconnection came after the system was infected, disconnection is a non-factor, IMO.
FWIW: Your title reflects one thing as the topic, while your comments do not even mention the content of the BSOD.
I suggest that you take care of the possible malware issues first...before attempting to focus on any issues that remain after the malware situation has been clarified.