dll errors PLEASE HELP ME:(((

Hi, I need help.
My computer is a Toshiba Satellite running windows XP sp3.

I've started having problems with the wbemcomn.dll file every time I turn on the computer I get an error msg. that reads This app has failed to start because wbemcomn.dll was not found.Re- installing the app may fix this problem.Any time I try to download something I get the same message?I have gotten messages several times that says my virtual memory is low.I ran a RSIT.exe scan and have attached the Hijack this log.Could you please advise me how to fix this problem.I am not a computer whiz just a single mom trying to get this darn computer to work????NEED YOUR HELP.cant afford to get someone to help...