We'll make you a run a scan overnight. As this is a Netbook, please keep it plugged in to the charger so it doesn't turn off during the scan. I recommend you to leave that scan running overnight since it can be a pretty lenghty one. Open an elevated command prompt (like you did for the SFC scan) and enter this command:
From there, accept to schedule the scan for the next restart (Enter y then press on Enter) and restart your computer, the scan will be launched automatically. Please do not interrupt it for any reason there is as you could damage your HDD badly.
I ran chkdsk / r. There was no change in the speed of the netbook. Several times I did notice that there were some messages that indicated that a segment could not be read.
I am not sure that it will help you but I have noticed (1) I cannot create a system restore point; and (2) when I try to open the C: drive in Explorer, the computer locks up (it continues showing the spinning circle indicating that it is trying to respond, but never does nor let me do anything. I have to turn it off by holding the power button down.)
Also I noticed that the sfc scannow report indicates that there are a number of corrupt drivers. The last time this computer had major problems it was fixed by replacing corrupt and missing drivers.