Computer starting with only 15% memory and hangs after a while.

Hi guys,
I am having this issue for about 3 days. I did not install any new programs but upon startup everything hangs and the startup programs take very long to startup. First time i am encountering such an issue.

What i tried to do

1. I tried doing a system restore the first time around from safe mode. This problem started on 17/09/2013. so the last system restore available was on the 16/09/2013. worked fine after doing the system restore, so happily i shut down my com. the next day when i turned the com on, voila the problem is back again.

2. tried doing system restore but no more system restore points left.

3. did a pre-boot diagnostic --> everything was fine. no problems with anything

4. when the com was working fine, i did a virus scan with microsoft security essentials (updated) and everything seemed clean

5. Uninstalled most of my programs like spotify. steam, garena, my games

6. ran cc cleaner to rectify any registry errors but there were no errors

7. I have a feeling there is some malware running in the background, taking up the memory

If anyone has any ideas about the predicament i am in, please share with me. I am at my wits end. Thank you all so much :)

Stop receiving emails on this subject.

Task Manager Processes tab might be worth looking into in case some strange process is running in the back ground.

It may be worth running some file integrity scans using an elevated command prompt > sfc /scannow command, or the Dism /Online /Cleanup-Image /RestoreHealth command, etc. might take a few passes/restarts if there are any file problems.

Malwarebytes might also be worth a shot. :)