Hello Suraj,

Emails of this type typically are not related to any malware infections. They're simply scam emails sent to hundreds of thousands of users with an intention of tricking gullible people into paying for something that doesn't exist (e.g., removal of malware that doesn't exist, ransom demands for deletion of private data which supposedly been stolen, etc.) In other words, crooks try to scare recipients and lure them into paying for nothing.

I assume that emails you've received look something like this:

Example 1
Example 2
Example 3

In any case, you should ignore these emails. Moreover, if any of those (or similar ones) have any attached files, DO NOT open them - it may lead to actual malware infections.

Now when it comes to knowing if your system is clean or not, I suggest you scanning the system with multiple malware removal tools. And, of course, be sure to choose the respectable ones. Note that it is crucial to remove one malware removal tool before installing another in order to avoid interference. I advise you to use Combo Cleaner as one of them.

Feel free to ask if you have any additional questions.