My PC has a message (Blocked, call I-888etc) help me to unlock my PC please

Is it really blocked? Or does it just say it is? I'm guessing it says it is but isn't. I would NOT click on that or call them. Shut the machine down and reboot, depending on what version you are running sometimes three reboots will let the browser go back to its original home page.

If its really locked.. you are screwed, then its ransomware where they blackmail you to give you control back.

If that happened I'd zero out the drive and do a clean wipe... reformat and reload everything. And make sure you get a better antivirus, anti malware package than you had.

Can you tell us the actual message you are getting ?