If the only problem is with the ACPU usage.. then I recommend choose to close most of the known proccesses by terminating the programs..... See if there is an improvement in the resource utilisation....

As mentioned memory corruption could at times be the cause of high CPU utilisation... It could also be as a result of ongoing background scan (Either virus or trojan).....

Just in case u feel u r still hounded by SPYWARE suggest you to install CWS SHREDDER .. it is a wonderful toold for detecting and deleting CWS torjans.....

In my case Adawre was not able to detect and delete trojans indentified by CWShredder.....

If possible paste the hijackthis log.. then we can come to a conclusion if u are really hit by some spywares / torjans.....