First, make sure that AVG/AVAST has not installed any browser extension...
https://thehackernews.com/2019/12/avast-and-avg-browser-plugins.html
Second, download Malwarebytes and run(as Admin.) a deep scan.
Third, keep your TASK Manager open and see what processes are running during these spikes. Look out for any weird process behaviour like sudden jump in CPU Time. CPU Time can be activated from "View > Select Columns". Set it in descending order to see maximum process consumption. Also check for any process appearing suddenly during a spike, for seconds maybe.
Fourth, check your System Logs in Event Viewer to find any anomalies during the spikes.
Fifth, run this software as Admin., and see if you find anything interesting...
https://www.resplendence.com/whysoslow
Do all of the above and let us know and we can proceed from there. Please reply to each step individually in your response.
Definitely not perfect but I am at least smart enough to check any advanced options when I install anything and I did not install any browser extensions. I checked anyways and did not find anything. I am sort of surprised, I haven't used AVG or really any other anti virus since 2012 and I remember it being reliable (atleast with my circle of teen tech savvy friends, but after installing malwarebytes, running it as admin and running a full scan, 19 threats. Here are the results, I left the notifications off because I am fairly sure I did that myself and uhm.. I ACCIDENTALLY left the last 2 for obvious reasons.. hopefully not judged harshly on those. I'll let you know if this works.
-Scan Summary-
Scan Type: Custom Scan
Scan Initiated By: Manual
Result: Completed
Objects Scanned: 623778
Threats Detected: 19
Threats Quarantined: 14
Time Elapsed: 2 hr, 3 min, 41 sec
-Scan Options-
Memory: Enabled
Startup: Enabled
Filesystem: Enabled
Archives: Enabled
Rootkits: Enabled
Heuristics: Enabled
PUP: Warn
PUM: Warn
-Scan Details-
Process: 0
(No malicious items detected)
Module: 0
(No malicious items detected)
Registry Key: 9
Trojan.FakeMS, HKLM\SOFTWARE\MICROSOFT\WINDOWS NT\CURRENTVERSION\SCHEDULE\TASKCACHE\TREE\Microsoft\Windows\Application Experience\StartupCheckLibrary, Delete-on-Reboot, 3109, 676733, , , ,
Trojan.FakeMS, HKLM\SOFTWARE\MICROSOFT\WINDOWS NT\CURRENTVERSION\SCHEDULE\TASKCACHE\TASKS\{8D0BAE8B-B751-4189-9B98-C9A5ECE7DBA6}, Delete-on-Reboot, 3109, 676733, , , ,
Trojan.FakeMS, HKLM\SOFTWARE\MICROSOFT\WINDOWS NT\CURRENTVERSION\SCHEDULE\TASKCACHE\LOGON\{8D0BAE8B-B751-4189-9B98-C9A5ECE7DBA6}, Delete-on-Reboot, 3109, 676733, , , ,
Trojan.FakeMS.TskLnk, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache\Tree\Microsoft\Windows\Application Experience\StartupCheckLibrary, Delete-on-Reboot, 4095, -1, 0.0.0, , action,
Trojan.FakeMS.TskLnk, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache\Tasks\{8D0BAE8B-B751-4189-9B98-C9A5ECE7DBA6}, Delete-on-Reboot, 4095, -1, 0.0.0, , action,
Trojan.FakeMS.TskLnk, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache\Logon\{8D0BAE8B-B751-4189-9B98-C9A5ECE7DBA6}, Delete-on-Reboot, 4095, -1, 0.0.0, , action,
Backdoor.Agent, HKLM\SOFTWARE\MICROSOFT\WINDOWS NT\CURRENTVERSION\SCHEDULE\TASKCACHE\TREE\Microsoft\Windows\WDI\SrvHost, Delete-on-Reboot, 3583, 653658, , , ,
Backdoor.Agent, HKLM\SOFTWARE\MICROSOFT\WINDOWS NT\CURRENTVERSION\SCHEDULE\TASKCACHE\TASKS\{1399F039-D490-4C72-B45D-F29F1141E4DC}, Delete-on-Reboot, 3583, 653658, , , ,
Backdoor.Agent, HKLM\SOFTWARE\MICROSOFT\WINDOWS NT\CURRENTVERSION\SCHEDULE\TASKCACHE\LOGON\{1399F039-D490-4C72-B45D-F29F1141E4DC}, Delete-on-Reboot, 3583, 653658, , , ,
Registry Value: 0
(No malicious items detected)
Registry Data: 3
PUM.Optional.DisabledSecurityCenter, HKLM\SOFTWARE\MICROSOFT\SECURITY CENTER|ANTIVIRUSDISABLENOTIFY, No Action By User, 13371, 293294, 1.0.15708, , ame,
PUM.Optional.DisabledSecurityCenter, HKLM\SOFTWARE\MICROSOFT\SECURITY CENTER|FIREWALLDISABLENOTIFY, No Action By User, 13371, 293295, 1.0.15708, , ame,
PUM.Optional.DisabledSecurityCenter, HKLM\SOFTWARE\MICROSOFT\SECURITY CENTER|UPDATESDISABLENOTIFY, No Action By User, 13371, 293296, 1.0.15708, , ame,
Data Stream: 0
(No malicious items detected)
Folder: 0
(No malicious items detected)
File: 7
Trojan.FakeMS, C:\WINDOWS\SYSTEM32\TASKS\Microsoft\Windows\Application Experience\StartupCheckLibrary, Delete-on-Reboot, 3109, 676733, 1.0.15708, , ame,
Trojan.FakeMS.TskLnk, C:\WINDOWS\SYSTEM32\STARTUPCHECKLIBRARY.DLL, Delete-on-Reboot, 4095, 676770, 1.0.15708, , ame,
Trojan.FakeMS.TskLnk, C:\WINDOWS\SYSTEM32\TASKS\Microsoft\Windows\Application Experience\StartupCheckLibrary, Delete-on-Reboot, 4095, -1, 0.0.0, , action,
Backdoor.Agent, C:\WINDOWS\SYSTEM32\TASKS\Microsoft\Windows\WDI\SrvHost, Delete-on-Reboot, 3583, 653658, 1.0.15708, , ame,
Backdoor.Agent, C:\WINDOWS\SYSTEM32\WINSCOMRSSRV.DLL, Delete-on-Reboot, 3583, 653659, 1.0.15708, , ame,
CrackTool.SpectraLayers.Keygen, D:\VEGAS\SONY VEGAS PRO 13.0 BUILD 453 (X64) + PATCH DI\KEYGEN & PATCH BY DI\KEYGEN.EXE, No Action By User, 8524, 127005, 1.0.15708, D23167EED5156BFCFBB3FECD, dds, 00485863
CrackTool.SpectraLayers.Keygen, D:\VEGAS\SONY VEGAS PRO 13.0 BUILD 453 (X64) + PATCH DI\KEYGEN & PATCH BY DI\KEYGEN.ZIP, No Action By User, 8524, 127005, 1.0.15708, D23167EED5156BFCFBB3FECD, dds, 00485863
Physical Sector: 0
(No malicious items detected)
WMI: 0
(No malicious items detected)
(end)