PC freezing up during (or just after) startup

[Tordal]

My PC has been acting strange the past couple of days. It started with it freezing during startup. A push of the reset button fixed it.

The last 2 days the PC has booted up and logged into Windows (10), and then the mouse pointer starts lagging really bad (like 1-3 fps), and I can't click anything. It seems to happen every time the PC has been switched off for a while (20-ish hours).

 

I've got Crucial Ballistix Tactical Tracer RAM, which has activity leds blinking, and all the lights are blinking so fast it looks like they're just all switched on. Again, a reset fixes it and I'm able to use the PC as normal.

 

Has anyone got any ideas on what this might be?

[J400]

I'm not sure but it sounds like one of the ram slots might be going out slowly, but that's just speculation. try taking out the last ram stick (2nd if you have 2 sticks, 4th if you have 4 sticks) and swapping them around and removing them one by one, one of the dimms could also be corrupt, or your os might be corrupted and might need a fresh install. a laggy mouse can be a product of not having enough memory, or none at all, leading to your cpu having to use the tiny amount of memory it has, and then using your storage in place of physical memory. there could also be some type of malware issue, try checking your cpu usage in task manager to see if something is eating it up.

[Tordal]

Thanks for the tip. Turned out it was Antimalware Service Executable that sat there eating 30-ish % of my CPU and slowing everything down. 

http://answers.microsoft.com/en-us/protect/forum/protect_defender-protect_scanning/how-to-stop-antimalware-service-executable-from/a3a57d31-4687-43c0-b274-261da7d89245