Success, I have managed to clean it out nicely and no more problems with it. The problem was also linked to an IE plugin that Adaware removed, a DLL file, and also and a lopsearch.exe file in the Application Data folder. I have my younger siblings also using this PC and its possible they may have unwillingly clicked something or said "yes" to one of those ominious prompts to install something. I decided to post part of the log file of my ad aware cleaning job here.
Removing selected components:
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Deleting

oubleclick,3,file,2,,D:\Documents and Settings\Administrator\Cookies\administrator@doubleclick[1].txt,
Deleting:Other,3,file,2,,D:\Documents and Settings\Administrator\Cookies\administrator@valueclick[1].txt,
Deleting:Lop,3,file,2,,D:\Documents and Settings\Administrator\Application Data\lopsearch.exe,203
Deleting:Lop,3,file,2,,D:\Documents and Settings\Administrator\Application Data\plg_ie0.dll,203
Deleting

oubleclick,3,file,2,,D:\Documents and Settings\Vanisha\Cookies\vanisha@doubleclick[1].txt,
Deleting:Other,3,file,2,,D:\Documents and Settings\Vanisha\Cookies\vanisha@valueclick[1].txt,
Deleting

oubleclick,3,file,2,,D:\Documents and Settings\Dharmesh\Cookies\dharmesh@doubleclick[1].txt,
Deleting:Other,3,file,2,,D:\Documents and Settings\Dharmesh\Cookies\dharmesh@valueclick[1].txt,
Deleting:Lop,1,HKEY_CLASSES_ROOT,2,clsid\{9b35a850-66ab-4c6d-8a66-136ecadcd904},,
Deleting:Lop,1,HKEY_CLASSES_ROOT,2,clsid\{d44b5436-b3e4-4595-b0e9-106690e70a58},,
Deleting:Alexa,1,HKEY_LOCAL_MACHINE,2,software\microsoft\internet explorer\extensions\{c95fe080-8f5d-11d2-a20b-00aa003c157a},,
Deleting:Lop,1,HKEY_CURRENT_USER,2,software\microsoft\windows\currentversion\backup,,
Deleting:Lop,1,HKEY_LOCAL_MACHINE,2,software\microsoft\windows\currentversion\explorer\browser helper objects\{d44b5436-b3e4-4595-b0e9-106690e70a58},,
Deleting:Lop,1,HKEY_CURRENT_USER,2,software\trinityayb,,
Deleting:Lop,1,HKEY_CLASSES_ROOT,2,swish.browserhelper,,
Deleting:Lop,1,HKEY_CLASSES_ROOT,2,swish.browserhelper.1,,
Deleting:Lop,1,HKEY_CLASSES_ROOT,2,swish.toolband,,
Deleting:Lop,1,HKEY_CLASSES_ROOT,2,swish.toolband.1,,
Initializing:Lop,2,HKEY_LOCAL_MACHINE,2,software\microsoft\internet explorer\toolbar,{9b35a850-66ab-4c6d-8a66-136ecadcd904},
Task completed on9:35:02 AM
Done.