Strange sound !? (Hacker) HELP

[ColopiX]

Hello guys,i have noticed some strange sound coming from my speakers like opening a folder 1or 2 tiimes and than the sound disappear.
-I do not get this sound whole time its just randomly appear while i am playing games,or just working in browser.Also my browser Chrome or Mozila sometimes lag like hell.
-I have this problem for 2-3 weeks and i though it is some bug from the windows but today my eset smart secirity antivirus have blocked some user.
-Also my PC sometimes lag.Scaneed with ADW Cleaner nothing,eset nothing...no viruses just this message from eset:

My eset says Network Threat Blocked
TCP SYN Flood Attack
Source: My router ip adres
-What should i do pls help me i have files on my HDD that i need so much.I dont want to lose them

On my router i have conected using cable 2 PC and 3 smartphones using Wi-Fi

 

[USAFRet]

What should i do pls help me i have files on my HDD that i need so much.I dont want to lose them

This is fixed by having a backup.

 

[Designful]

I'd start by checking the extentsions of your browsers and removing all the unwanted extensions, then uninstall the browsers, uninstall any programs you question the validity of, install malwarebytes, and hope that fixes it.

I've had a couple adware spam my broswer and stuff and by doing above cleaned everything and haven't had a problem for quite some time.

 

[ColopiX]

I'd start by checking the extentsions of your browsers and removing all the unwanted extensions, then uninstall the browsers, uninstall any programs you question the validity of, install malwarebytes, and hope that fixes it.

I've had a couple adware spam my broswer and stuff and by doing above cleaned everything and haven't had a problem for quite some time.

Ok i will try that.Also my Eset antivirus has founded 9 viruses now WTF....