PCAntiSpyware is a cloned version of the rogue anti-spyware threat PCCleaner, which is as malicious as its counterpart. It infiltrates computers via web browser security holes; it is also dropped by several trojans.
PCAntiSpyware may hijack your desktop and flood you with fake security notifications to lure people into downloading it. Pop-ups displayed by this malware are similar to MS Windows notifications and security alerts. Do not trust PCAntiSpyware nor its clone PCCleaner; essentially, it is a scam to milk money.